LOS ANGELES -- "I was staying a few blocks from the explosion, but didn't hear it," wrote Daniel Brinkenhoff, a 29-year-old runner, to The Huffington Post. "I saw all the cop cars and ambulances streaming down huntington ave and you could smell the smoke in the air. Crazy. Pray that not too many people were injured."
Brinkenhoff, who had flown in from Los Angeles for the race, was already back at his friend's home across from the Prudential Mall in Boston when someone texted him the news about the explosion. By the time he was corresponding with HuffPost, he was on the Acela Train to New York City and noted that he wasn't getting service on his Verizon phone.
He was just one of hundreds of Angelenos who had traveled across the country to participate in the historic Boston race and found themselves in the midst of mayhem after two bombs detonated four hours into the marathon.
Like Brinkenhoff, UCLA psychology professor Bruce Chorpita was already safe in his hotel room when he heard the bombs go off, as was his brother who was also running.
"I crossed the finish line at 3:36 and the bomb went off on 4:09," he said to HuffPost on the phone. "My brother went through 15 minutes before the bomb went off, and he had just gotten through the door at the hotel when we heard the blast."
"Of course you think about [the what-ifs] -- I was just there several times today," he continued. "But we were lucky, and some people were not, and I'm thinking more about the people who were not."
The first-time Boston marathoner and father added, "I'm eager to see my kids and wife. I always am when I travel, but now especially so."
As of Monday evening, Chorpita was hunkered down in his room at the Taj Hotel, which is a block and a half away from the finish line. Chorpita explained that authorities locked down the city within a 15 block radius of the explosion scene and that the streets were empty. The hotel had advised guests to remain indoors while authorities continue to clear the area. Chorpita expects to be able to fly back to Los Angeles Tuesday, as he originally planned.
(Story continues below)
Boston Marathon Explosion (GRAPHIC PHOTOS)
Back home, Los Angeles County Sheriff Lee Baca expressed his sympathy for the victims and first responders affected by the bombs. Baca is increasing police patrols near places with a lot of foot traffic, like government buildings, shopping centers, sports stadiums and public transit. He also encouraged Angelenos to report anything that "just doesn't look right."
Los Angeles Police Chief Charlie Beck also decided to deploy bomb-squad personnel, including dogs, at sporting events like Monday's game at Dodger Stadium.
“We will be increasing deployment at all scheduled sporting events in the near future,” Beck said to The Los Angeles Times. “I’ve already been in contact with the Dodgers about this.”
The tragedy, which so far has claimed two lives and seriously injured dozens of others, has strengthened the resolve of at least one LA runner. Arkady Hagopian estimated that he had just finished the race about 10 to 15 minutes before he heard the first explosion.
"At first we thought that baseball game had fired a cannon, but then we saw the first responders," said Hagopian to HuffPost over the phone. He was about two or three blocks away from the explosion with two other friends who had had run the race with him. Their first instinct was to look for the other members of their group, whom they were able to find after 20 minutes.
"Whoever did this is trying to break people's spirits, but it's not going to happen," he continued. "It only brings people closer." A second-time Boston marathoner, 33-year-old Hagopian added, "I was on the fence, but now it's definite. I will sign up next year."
This story was updated with interviews of LA runners at the Boston Marathon. Check back for more breaking news updates.
HuffPost Readers: If you or anyone you know is in Boston today, we want to hear from you about what's happening there. Send your stories, eyewitness accounts, photos, videos, and anything else you want to share here. Include a phone number if you'd like to be interviewed. Let us know if you want to remain anonymous.