Seven friends and relatives of an illegal immigrant accused of killing a California police officer the day after Christmas were indicted on federal charges for allegedly helping the man attempt to flee to Mexico, federal officials said Friday.

The group is accused of helping Gustavo Perez Arriaga, 33, after he allegedly shot and killed Newman Police Officer Ronil Singh during a traffic stop.

“When individuals act to thwart law enforcement’s efforts, they undermine the safety of those officers and the public as a whole,” U.S. Attorney McGregor Scott in a statement. “Today’s indictment is a significant step toward holding accountable those who chose to harbor and conceal the man accused of killing a police officer in Newman — Corporal Ronil Singh.”

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Those indicted include: Erik Razo Quiroz, 29, of Merced; Adrian Virgen-Mendoza, 25, of Fairfield; Conrado Virgen Mendoza, 34, of Chowchilla; Erasmo Villegas-Suarez, 36, of Buttonwillow; Ana Leydi Cervantes-Sanchez, 31, of Newman; Bernabe Madrigal-Castaneda, 59, of Lamont; and Maria Luisa Moreno, 57, of Lamont.

All seven were charged with conspiring to hide Perez Arriaga, and smuggle him back to Mexico, according to the Fresno Bee. Members of the group allegedly gave Perez Arriaga clothes, money and a new phone and hid his pickup truck, among other efforts.

Razo Quiroz was also charged with being a felon in possession of a firearm and being an alien in possession of a firearm, court documents said.

The seven also face state charges for helping Perez Arriaga try to flee to avoid prosecution and lying to investigators.

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Perez Arriaga shot Singh after the officer stopped his vehicle to check if he was driving drunk, according to prosecutors. He had two previous drunken driving arrests, authorities said.

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The sheriff leading the investigation has blamed California's sanctuary law for preventing local authorities from reporting Arriaga to U.S. immigration officials for the two previous arrests. If he had been deported, the sheriff said, Singh would still be alive.

"We can't ignore the fact that this could have been preventable," Stanislaus County Sheriff Adam Christianson said in December, asking why the state was "providing sanctuary for criminals (and) gang members. It's a conversation we need to have."

The Associated Press contributed to this report.