Octaviano Juarez-Corro, 48, is accused of killing two people and wounding three others at a Memorial Day 2006 picnic at Milwaukee’s South Shore Park on Lake Michigan, the FBI said in a news release.
His estranged wife was one of the people injured with two gunshot wounds to the chest, the FBI said.
The FBI said hundreds of people were in the park at the time of the shooting.
Juarez-Corro was added to the Ten Most Wanted Fugitives list in September 2021.
After receiving a tip from the public, the FBI and Mexican authorities located Juarez-Corro on Thursday in Zapopan, Guadalajara, Mexico, the release said.
A felony arrest warrant was issued in Milwaukee County Circuit Court charging Juarez-Corro with two counts of first-degree intentional homicide and three counts of first-degree attempted intentional homicide, according to the FBI.
A federal arrest warrant charges him with unlawful flight to avoid prosecution, the FBI said.
Whether Juarez-Corro has an attorney and the status of his extradition process were not clear.
“The FBI has a long reach and extraordinary law enforcement partnerships across the globe. I commend the tireless efforts of all our partners from Milwaukee to Mexico in closely coordinating with the FBI in capturing this wanted fugitive and helping to bring this violent offender to justice, as well as closure to the victims and their families.”
Juarez-Corro was the 525th person added to the Ten Most Wanted Fugitives list, which was created in 1950, the release said.
The FBI had offered a $100,000 (A$141,466) reward for information leading to his arrest.