A Los Angeles Dodgers fan was stabbed to death after his team played the San Francisco Giants at AT&T Park on Wednesday night, and police said today it appears the killing was preceded by an argument over the teams' rivalry.

Jonathan Denver, 24, was stabbed around 11:35 p.m. near Third and Harrison streets, four blocks from the ballpark where the Giants and Dodgers had played earlier in the night, with the Giants winning 6-4.

Denver, who was wearing Dodgers clothing, was with his father, brother and two other people at the time.

They had left the game in the eighth inning and had gone to a nearby bar, San Francisco police Chief Greg Suhr said at a news conference this morning.

After leaving the bar, the victim's group crossed paths with a group of Giants fans and "there was a back-and-forth about the Giants-Dodgers rivalry," Suhr said.

The argument deteriorated into a fight in which no one was seriously hurt, he said.

Suhr said what happened next remains unclear, but that one of the groups followed the other group and a second altercation ensued minutes later, during which Denver was stabbed.

He was taken to San Francisco General Hospital, where he died.

Two people were detained at Second and Howard streets and were being interviewed this morning, but have not been arrested, Suhr said.

He said police are still seeking two other people believed to be connected to the case.

Suhr did not release any information about the suspects except that they had come to San Francisco in a vehicle registered in Lodi.

Denver worked as a plumber's apprentice for North Coast Plumbing, Heating & Sheet Metal Inc. in Fort Bragg, according to an employee at the company.

Suhr said the Police Department has been assigning extra officers to this week's games between the Giants and Dodgers, two National League West division teams with a long and storied rivalry.

Denver's death is the latest violent incident to mar the rivalry.

In 2011, Giants fan Bryan Stow was beaten after the team's season opener at Dodger Stadium in Los Angeles, and suffered severe brain injuries.

The Giants held a fundraiser for Stow at Tuesday's game against the Dodgers and have two more planned at tonight's game and during their season finale against the San Diego Padres.

Suhr said police will continue sending undercover officers wearing Dodgers gear to tonight's game, along with other plainclothes officers, to ensure safety in and around the ballpark.

"There's no place at these games for violence," he said. "Nobody's life should be at stake."


Sign up for our weekly newsletter and join the conversation on Facebook.

Check out some of our most popular blogs:

     We Built a Stronger SF Economy on Smart Government Investments

     The BART That Could Have Been

     Run For Your Life! (For Fun)

     Love Muni, Hate Muni or Somewhere in Between? Let the SFMTA Know!