A Santa Rosa detective testified Monday that the cousin of a murder suspect initially claimed responsibility for the crime in a series of text messages to a young woman he was trying to impress.

As it turned out, the young woman already had a boyfriend - the victim, 18-year-old Luis Suarez.

After reading texts from then 17-year-old Marco Meza saying, "I shot that fool," the girlfriend called police, who arrested him along with his cousin, the man now facing charges for the fatal shooting, Fernando Mendoza, 22 of Santa Rosa.

"He tried to impress (the girlfriend)," Detective Brad Conners testified at Mendoza's preliminary hearing about the bragging that led to his arrest. Police believe Mendoza actually did the fatal shooting.

The detective said Mendoza and Meza met the day after the April 6, 2009 drive-by and Mendoza gave his younger cousin the details. Meza then began texting the girlfriend, claiming credit for the killing. He apparently didn't know her connection to Suarez.

"He told me he was a Norteno," Meza said in one of the messages. "So I let him have it."

Meza told a different story after he was caught with Mendoza and another woman as they tried to get rid of the red Lexus police said was used in the South Park neighborhood shooting.

Meza said he was in Lake County when Suarez was shot, Conners testified under questioning from prosecutor Victoria Shanahan.

Meza then described for police his conversation with Mendoza the next day. He said his cousin told him he had been cruising in the Lexus, registered to his mother, when he spotted Suarez and another man walking down the street, "mad-dogging" or staring at him.

Mendoza continued to nearby Martin Luther King Junior Park and then returned to the area of Grand Avenue and Pressley Street, where he saw Suarez, a former Ridgway High student, walking alone.

Mendoza told Meza that he pulled up to the sidewalk, got out and confronted Suarez about what gang he was in, Conners testified.

When Suarez told him he was a Norteno, Mendoza said he was too, "disguising" his membership. Suarez apparently didn't believe it and took off running, Conners said.

Then Mendoza allegedly drew a .38 caliber revolver and fired once at Suarez, who fell to the sidewalk. Mendoza walked up to him and fired three more bullets into his torso, Conners said Meza told him.

Suarez died at the scene.

Two days later, when Meza and Mendoza were trying to sell the Lexus on Santa Rosa Avenue, Meza said Mendoza pointed to a newspaper article about the killing and said "That's the fool I shot right there."

Jailhouse telephone conversations between Mendoza, known to friends as "Yogi," and Montez seemed to confirm that police had the right man.

Mendoza faces up to 50 years to life in prison if convicted of first-degree murder and participating in a gang.

Mendoza's lawyer, Steve Turer, said police had the wrong man. He suggested Meza did the shooting. Meza has pleaded to lesser charges and is awaiting sentencing.