On Saturday, the brothers’ neighbors gave a harrowing account of having heard banging at their door early Monday, and opening it to find the older brother, his face and head covered with blue and white masking tape, his hands tied behind him with white string. Behind the gag, they said, they heard him cry, “Ayúdame!” (“Help me!”). They took him in, cut the bindings and called the police, spawning a weeklong investigation that led to the arrest of seven of the gang members late Thursday and early Friday.

Police Commissioner Raymond W. Kelly said Saturday that those suspects had “made statements implicating themselves in this crime.” An eighth suspect, Elmer Confresi, 23, turned himself in on Saturday, while the ninth, Rudy Vargas-Perez, 22, reneged on a promise made through a lawyer to turn himself and remained at large, Mr. Kelly said.

Besides Mr. Mendez and Mr. Confresi, the suspects are David Rivera, 21, who had prior arrests for weapons possession and robbery; Bryan Almonte, 17; Steven Caraballo, 17; Elin Brayon Cepeda, 16; Nelson Falu, 17; and Denis Peitars, 17, all of the Bronx. They were still awaiting arraignment on Saturday night; officials said that the charges included kidnapping and sodomy, and that all would be charged as adults and with hate crimes.

“Like many New Yorkers, I was sickened by these antigay crimes,” Mayor Michael R. Bloomberg said Saturday afternoon. “The heartless men who committed these crimes should know that New Yorkers will not tolerate them.”

Christine C. Quinn, the City Council speaker, who is gay, added: “These crimes are not jokes. They are not games. They are things that eat away at the fabric of our city.”

Mr. Mendez, who the police said was the ringleader and was known by the street name “Cheto,” lived several miles away from the crime scene, in Bedford Park. Neighbors on his block, marred by graffiti and the scene of open drug markets, said that he had a crew of younger friends who were often with him but that he spent most of his time elsewhere. “He tried to look gangster,” Mr. Perez said. “He walked around like he was one of the neighborhood thugs.”

Several other suspects lived in the blocks surrounding Osborne Place, near the man known as “la Reina,” who worked at an optometrist’s store in the Parkchester section. Every day, he stopped by El Tio grocery, the bodega on the ground floor of his building, for juices, sandwiches and small talk, according to the manager, Xavier Peña. “He was a good friend,” Mr. Peña said. “He’s a very, very nice guy. He called me Papi, Papi.”