Three and half years ago, the Seattle-Tacoma area was paralyzed as police searched for a cop-killer, much like greater Los Angeles this past week. On a Sunday morning in 2009,  a gunman walked into a coffeshop in Parkland, Wa., fired on a group of police officers, killing four of them, and fled in a waiting vehicle.

For 48 hours, police throughout the region were focused on little else. They searched locations up and down the I-5 corridor near Lake Washington, the University of Washington, as well as closer to the original shooting near Tacoma.

The community lived in fear. And Twitter quickly became a clearinghouse for information. Organizing under the hashtag #washooting, citizens and journalists alike shared updates and expressed their condolences and fear.

When Seattle Times Editor David Boardman addressed the Seattle Chamber of Commerce after receiving the Pulitzer Prize for the paper’s coverage, he said, “First of all, I want to say this belongs to all of you. We want the whole community to share in this prize.”

The Seattle Times included portions of the Twitter stream in its supplemental entry to the Pulitzer Board.

Twitter played a slightly different role in Los Angeles this past week, where law enforcement was also hunting across a widespread area for Christopher Dorner, a man who had killed cops. In that manhunt's final hours, the San Bernardino County Sheriff’s Office asked the media to stop tweeting.

Law enforcement hoped to prevent any accidental release of strategic information, like how many SWAT officers were assembling and what type of assault they were planning on the cabin where Dorner had holed up.

It was a ridiculous request, many now agree in hindsight. Twitter is one way that people talk to each other. And people can't possibly not talk about the most gripping and dramatic events in their community.

It was clear throughout the manhunt that Twitter has "revolutionized" the way the public gets and shares information about breaking news events, said Robert J. Lopez, a Los Angeles Times reporter who mans the LA Now news blog for the paper, in addition to his investigative work. Twitter quickly became the place where people shouted back challenges and criticisms of law enforcement. "They had legitimate questions," he said, during a phone interview on Thursday.

Twitter took on a different role in LA. Rather than one single organizing hashtag, there were many different hashtags, including #manhunt, #dorner, and at the end #bigbear.

And rather than unifying and reassuring the community, Twitter became the safe and acceptable space for folks to criticize law enforcement, express their doubts about the narrative that was being reported and share their own information.

Lopez, who Tweets using an older version of TweetDeck, said he was impressed by the number of citizens re-tweeting his posts. People naturally wanted to be part of sharing new information and prompting reporters to pursue specific lines of inquiry.

When San Bernardino officials asked journalists to stop tweeting on Tuesday night during the standoff in the mountains, Lopez didn't notice much of an impact. "I'm not really sure how many of us knew that request was out there," he said. "I didn't hear about it until afterward."

As the pace of new information dwindles now that Dorner is confirmed dead, the #Dorner hashtag remains active. On Thursday it was mostly dominated by people who are still suspicious that law enforcement deliberately burned the cabin to the ground in an act of revenge.

The San Bernardino Sheriff’s Department and the L.A. Police Department deny this, stating that the fire was a result of tear gas canisters and other incendiary canisters fired into the cabin.

What do we learn by comparing the use of Twitter during the two different manhunts, Seattle in 2009 and LA in 2013? Twitter morphs to reflect a specific community or event. Seattle, a tech haven of early adopters, is more homogenous in that respect, and in 2009 Twitter users were a smaller group. As a community it reacted to the murder of cops with a more unified voice. In LA, a sprawling metropolis, the reaction to events was more diverse and unpredictable. And Twitter became the place to start that investigation.

"Twitter is like a roadmap," Lopez said. It's full of signs and signals that need to be vetted and interpreted.