Detective: Defendants instilling fear in fatal Modesto park attack

An investigator on Wednesday testified that three defendants stabbed to death a teenager at a Modesto park because they were trying to instill fear on behalf of the Norteño street gang.

Detective Robert Gumm, a Modesto police gang investigator, said Taylor Koplen, Jacob Segura and Juan Garcia are documented Norteño gang members. He said the three defendants were acting as gang foot soldiers when they attacked Tylor Crippen, 18, at Creekwood Park because the stabbing maintained the gang’s stronghold in the neighborhood.

“That’s what gangs are all about, controlling a neighborhood through fear and intimidation,” Gumm told the jury.

During cross-examination, the detective said he has no information that gang leaders sanctioned the attack on Crippen. He also testified that he doesn’t know how or when the defendants became Norteño gang members.

“I can’t tell you how any of them became gang members,” Gumm said on the witness stand. “I can tell you they are gang members.”

Koplen, Segura and Garcia are on trial. They are accused of murder in Crippen’s stabbing. They also face charges of robbery and two counts of attempted robbery, along with enhancements of committing crimes for the benefit of the Norteño street gang.

The detective looked into the defendants’ criminal backgrounds and interactions with law enforcement, basing his opinion on several dozen police reports. He said he also gathers intelligence on gang activity and membership through informants who are sometimes paid by law enforcement.

Gumm testified that his department’s policy to determine whether someone is a documented gang member closely resembles the criteria used by the state Department of Justice. The Modesto police criteria, however, has been adjusted in the past few years, as recently as Oct.1.

The criteria Gumm used to determine whether Koplen, Segura and Garcia are gang members was the criteria used when the murder occurred nearly two years ago. If a suspect meets two of 10 criteria, Modesto police consider the suspect a documented gang member.

For instance, police reports indicated Garcia was found with known gang members several times. He once was suspected of spray-painting gang graffiti and found with black spray paint on his hands. On another occasion, Garcia was found with Segura, a known gang member, at Creekwood Park after he was warned that associating with gang members at the park was a probation violation, according to a police report.

During cross-examination, Gumm said Segura doesn’t have any gang tattoos, even though gang members are known to have have tattoos to mark their affiliation.

The detective said gang members act with a “pack mentality,” meaning when one responds with violence, the others must do the same. Gumm testified that the attack on Crippen shows the defendants were working together.

Previous testimony has indicated that one suspect held Crippen’s girlfriend at knifepoint, while two others chased Crippen into the park. The knife-wielding suspect then joined the chase into the park, where Crippen was stabbed.

“They were acting as one. They were working as a unit,” Gumm told the jurors.

When a targeted victim resists, the violence will escalate because it’s considered disrespect on the street. Gumm said gang members have to respond with force, even deadly force, or they’ll lose their grip on the neighborhood.

“That’s their park. That park is claimed by Norteños; it has been for years,” Gumm testified.

On the night of Jan.29, 2013, Crippen and his girlfriend were targeted by the defendants for a “pocket check,” a strong-arm robbery where gang members confront victims and demand they empty their pockets, Gumm said.

The crime is not intended to provide a big financial gain for the robbers. Gumm told the jurors that “pocket-check” robberies are more about instilling fear in the neighborhood.

Testimony in the trial is expected to continue Thursday in Stanislaus Superior Court.

This story was originally published October 22, 2014 at 4:38 PM with the headline "Detective: Defendants instilling fear in fatal Modesto park attack."