Giovanni Ramírez, 31, was "Suspect 1" in the brutal attack of Bryan Stow in the parking lot at the stadium on the rival teams' opener. He was charged with possession of a deadly weapon and was being held on $1 million bail, police said in a statement.
The arrest was the culmination of an investigation that spared no resources, authorities said. Police flooded Los Angeles with drawings and descriptions, and put up new billboards just last week. They also took in hundreds of tips.
In the end, it was a lead from inside law enforcement that led them to the man they say was the main aggressor in the grisly beating.
A tip from a parole officer late last week gave detectives the break they'd sought for seven weeks.
Ramírez, of Los Angeles, was arrested on Sunday. He was detained in an early morning raid by detectives and SWAT team members with a search warrant for an East Hollywood apartment building in what Police Chief Charlie Beck called a "huge step" in the investigation.
Beck choked back tears as he described getting a call at 7 a.m. Sunday from Assistant Chief Earl Paysinger, after putting 20 full-time detectives on the case who worked for more than 6,000 hours.
"He said the words I've been waiting for, for seven weeks," Beck said. "He said that we had Bryan's assault suspect in custody."
Ramírez was among several people detained for questioning after police served search warrants and seized evidence in two places, the apartment building and a home, police said in a statement. All but Ramírez were expected to be released, the statement said. Beck did not know if Ramírez had hired an attorney.
Police also seized evidence from both places.
A second warrant was served at a home, police said, but provided no further details. They also seized evidence from both places.
Beck said Ramírez had become familiar to many in Los Angeles as "Suspect 1" from flyers and billboards. They described the man as having a bald head, goatee, and tattoos on his neck. Both men were wearing Dodger jerseys during the attack. Rewards totaling $250,000 have been offered for information leading to arrests.
Two other suspects remained at large: Another man who took part in the beating and a woman who drove the two men from the stadium, police said.
Stow, a 42-year-old paramedic and father of two, was transferred to San Francisco General Hospital after he was initially treated at Los Angeles County-University of Southern California Medical Center, where doctors put him in a medically induced coma to help prevent seizures.
Doctors recently reported that Stow has been able to open his eyes, but he remained in critical condition. His mother Ann Stow said she knew police in Los Angeles would catch someone, and praised both their work and the way they dealt with her family.
"They were so compassionate with our family, and reached out to us, and made a promise that they were not going to rest until they got these guys," she told KCBS radio. "So that's how I put it out of my mind. I didn't think about it, I knew it was going to be taken care of, and obviously they did what they promised."
San Francisco Mayor Ed Lee said after hearing the news Sunday he called Los Angeles Mayor Antonio Villaraigosa to express his thanks for authorities' efforts and to congratulate him.
Giants fan Les Wong, 37 of San Francisco celebrated the news as he headed to the game.
"It's good to hear that they caught someone. That kind of thing doesn't belong in sports," said Wong, who was wearing a Giants hat and Giants T-shirt.
Following the attack, Beck beefed up security at Dodger Stadium to deal with fights that had been breaking out at games in recent years and complaints from fans of opposing teams of verbal abuse and threats.
Beck said Sunday that the new security is working.
"This is the safest stadium in this country here in these past series, and it will continue to be so," the chief said.
Based on reporting by The Associated Press. AP Writers Andrew Dalton, Christopher Weber and Thomas Watkins in Los Angeles worked on the story. John Marshall and Antonio Gonzalez contributed from San Francisco.