Ideally, every news reporter would adopt a Joe Friday approach, "All we know are the facts, ma'am." There's a place for commentary and opinion, but news reporting isn't that place. A well-written news article should present the facts and let the reader form their own opinions. Unfortunately, in my opinion, that doesn't happen much anymore.
Separating fact from opinion in news reports
There are certain instances where a writer must be especially careful about blurring facts and opinions, whether the opinions belong to her or to someone else. Generally, those instances involve cases where what is said could be damaging to someone's (or some company's) reputation. We can write about allegations, accusations, convictions and indictments as facts, but not the underlying actions unless we were personally witness to them and would be willing to testify to them under oath in a court of law. For example, "When I arrived on the scene, the fight was still in progress and Joe Smith was alternately shoving and being shoved by Sam Jones." I saw it, I would attest to it under oath, I can write it.
However, if, when I arrived, Joe and Sam were in handcuffs, all five people I asked said they saw the two shoving each other and described the altercation in detail, a police officer told me they were being arrested for disorderly conduct, public drunkenness and assault, and I heard Jones yell out, "Ness time I'll do more 'n jess shove you ta th' groun'," just before he vomitted onto the side of the police cruiser. I can not write a factual news article stating that Smith and Jones were shoving each other, that they were drunk, or anything about their specific actions (other than saying that Jones yelled out whatever I heard him yell).
I can write something like the following:
On Friday evening at approximately 11:45 p.m., the Rutland City Police arrested Joe Smith and Sam Jones outside of Notorious Nightclub on Main Street. The arresting officer, Detective Joe Friday, said the pair were being arrested for disorderly conduct, public drunkeness and assault.
Mike Jones, who said he was the brother of one of the accused, said "Sam wasn't doing nothing. Joe just walked up and hit him over the head with a beer bottle. Sam just turned around and pushed him away, you know, acting in self-defense." Four other bystanders, however, claimed to have seen Jones spit in Smith's face immediately prior to the altercation.
Bartenders could not say how many drinks were served to the pair prior to the trouble in the parking lot. Officers at the scene would not comment on the results of a breathalyzer test administered to Smith and Jones.
John Baptiste, who was behind the bar at the time said that Jones had been asked to leave the premises on several previous occasions, but could not say why.
In this example, I am not reporting as fact anything I didn't see. Instead I am reporting that an officer told me this, four bystanders (whose names and phone numbers I jotted down for my file) told me that, and Mike Jones told me something else. In this case, I could testify that these people told me those things, but I can't say for certain whether any of what they said is actually true or not. I did not personally, in my article, accuse anyone of anything or make assumptions about anyne's guilt or innocence.
It would be entirely wrong to write: On Friday evening at approximately 11:45 p.m., Joe Smith and Sam Jones were carted away in handcuffs after brawling in the parking lot of Notorious Nightclub on Main Street. Jones, a known trouble-maker, started the fight by spitting in Smith's face. Smith retaliated by hitting the larger man in the head with a beer bottle, but was shoved to the ground and could have been in for much worse if police had not arrived to break up the fight. While the majority of onlookers provided consistent descriptions of the fight, Jones' brother Mike seemed to leave out key pieces of the story to protect his big brother. Both men were drunk when they left the club and even the bartenders lost track of how much alcohol the men had been served that evening. Notorious Nightclub lives up to its name as events like those of last night seem to happen on a regular basis there. Perhaps, if the hired help were trained well enough to recognize when someone has had enough to drink, they could keep their patrons out of jail.
In the latter example, I have personally accused two men, Smith and Jones, of specific criminal actions. I have make actionable statements against the management and staff of Notorious Nightclub, accused Mike Jones of lying, and personally accused Smith and Jones of being drunk. Both I and my publisher could be sued over each of these statements, since they are all based on hearsay or unsubstantiated assumptions and damaging to someone's reputation. I don't know if the two men were drunk, if Mike Jones was lying, or if the four other bystanders were cousins of Smith and were lying on his behalf. Any of them might have been mistaken. I have one bartender's assertion that Jones had been removed from Notorious on previous occasions, but have personally interpreted that by calling Jones a known trouble-maker, another potentially actionable allegation on my part. While I might be able to successfully defend against civil suits against some of these claims, if the results of the breathalyzer tests were admitted and showed the men over the legal limit, for example, my allegation of them being drunk might get dismissed, but some are indefensible - was Mike Jones lying or simply mistaken?
Let's assume several weeks go by. Jones died from a subdural hematoma the next day, Smith is going on trial for murder. I can say that Smith has been arraigned for murder, he is being tried for murder, he has been accused of murder by the prosecutor, but I cannot call him a murderer, or say that he killed Jones. I can say that the coroner stated that the autopsy revealed the cause of death was a blow to the head consistent with being struck by a beer bottle, as Smith was alleged to have done two days prior to the Jones' death.
If Smith is convicted of murder, I still cannot call him a murderer with absolute impunity. I can say he has been convicted of murder, found guilty of murder, or is serving a life sentence for murder, but if the conviction were overturned later, my calling him a murderer outright would be proven to be incorrect.
In short, a factual news article can report allegations or statements made by others who are cited in the text, but should never make claims, accusations, or assumptions about events to which the writer was not personally a witness.
Although personal allegations against individuals are the most common instances where this comes into play, it also applies in other areas. I can't say for sure, for example whether cell phones cause brain tumors or not. I can say that 17 independent studies have found no evidence that cell phones cause brain tumors or that Mike Jones, brother of Sam Jones who was originally thought to have died of a subdural hematoma after being struck with a beer bottle, now claims that his brother's death was caused by a tumor triggered by his cellphone. "He never had no tumor before he got a cell phone," Jones shouted from the courthouse steps over the protests of his attorney.
The writer should let the reader know the source of every bit of information in the article that isn't widely known public knowledge. I don't need to provide a source for information like, "the President of the United States was born in Hawaii." If I wrote, however, "Hawaii remains the President's favorite vaction spot," I'd need to cite a source such as "he told Bill O'Reilly on The O'Reilly Show last night."