LOS ANGELES - A tip from a parole officer led to the arrest of one of the suspects in the attack on a San Francisco Giants fan outside Dodger Stadium after the rival teams' season opener, a brutal beating that prompted an outpouring of support for the victim and outrage in the sports world and beyond.

Police say Giovanni Ramirez, 31, is the suspect accused in the March 31 beating that left Bryan Stow with brain damage. Ramirez was booked for assault with a deadly weapon and is being held on $1 million bail.

Ramirez is believed to be the "main aggressor" in the Stow beating, Los Angeles Chief Charlie Beck said at an afternoon news conference at the stadium.

An emotional Beck hailed the work of 20 full-time detectives who he said have pursued 630 leads in the case. The police chief choked back tears as he described getting a call at 7 a.m. yester from Assistant Chief Earl Paysinger.

"He said the words I've been waiting for for 7 weeks. He said that we had Bryan's assault suspect in custody," Beck said. "This is a huge step."

Ramirez was among several people detained for questioning after police served search warrants, Los Angeles police Detective Jose Carillo said. Police said he was one of two suspects who have been sought in the case.

It's unclear whether the others detained were possible witnesses or suspects, said police Sgt. Kunch, who declined to give his first name per department policy.

Several search warrants were served at an apartment building, Kunch said, but he couldn't say how many people were detained or whether they are male or female.

Last week, doctors reported that Stow, a 42-year-old paramedic and father of two, is able to open his eyes but remains in critical condition after being transferred to San Francisco General Hospital.