SAN FRANCISCO (AP) — Leading Democrats — including San Francisco’s former mayor Sen. Dianne Feinstein — are joining mounting criticism of the city’s policy of refusing to cooperate with federal immigration officials when they request help in detaining a suspect thought to be in the country illegally.

The comments Tuesday involved the release last month of Juan Francisco Lopez Sanchez, a Mexican national who has been charged with murder in the shooting of a young woman last week at a San Francisco pier.

His release came despite a U.S. Immigration and Customs Enforcement request to keep him in custody so he could be deported for the sixth time.

Sanchez has served more than 17 years in prison for entering the country illegally and also has four felony drug convictions.

Criticism of San Francisco’s sanctuary city policy was expected from top Republicans such as Wisconsin Sen. Ron Johnson. But the policy is also drawing unexpected fire from Democrats, including both U.S. senators from California.

In addition, presidential candidate Hillary Clinton told CNN that San Francisco was wrong to ignore the ICE detainer request and release Sanchez from custody after local prosecutors dropped marijuana possession charges in April.

“The city made a mistake, not to deport someone that the federal government strongly felt should be deported,” Clinton said. “So I have absolutely no support for a city that ignores the strong evidence that should be acted on.”

Feinstein called on San Francisco Mayor Ed Lee to start cooperating with federal immigration officials who want to deport felons such as Sanchez who are in the country illegally. Feinstein served as San Francisco mayor from 1978 to 1988.

“I strongly believe that an undocumented individual, convicted of multiple felonies and with a detainer request from ICE, should not have been released,” Feinstein said. “We should focus on deporting convicted criminals, not setting them loose on our streets.”

The San Francisco mayor’s office said it has reached out to Department of Homeland Security officials to determine if there’s a way to cooperate with federal immigration officials while still maintaining the sanctuary policy.

“Mayor Lee shares the senator’s concerns surrounding the nature of Mr. Sanchez’ transfer to San Francisco and release,” said Christine Falvey, a spokeswoman for the mayor. “As the mayor has stated, we need to gather all of the facts as we develop potential solutions.”

Democratic Sen. Barbara Boxer, also from Northern California, said she asked Gov. Jerry Brown if state law was followed in the release of Sanchez.

“For decades, I have supported deporting violent criminals, and I have always believed that sanctuary should not be given to felons,” Boxer said.

San Francisco Sheriff Ross Mirkarimi has defended the release of Sanchez from jail and the city’s law requiring it to ignore ICE detainer requests. The sheriff said ICE could have obtained a warrant or court order to keep Sanchez in custody.

“ICE knew where he was,” Mirkarimi said Monday. He said he will continue to ignore ICE detainer requests and that federal officials can easily obtain court orders to keep deportation suspects in custody.

State and federal Republicans, meanwhile, said they would look into the matter.

Johnson, who chairs the Senate’s homeland security committee, criticized federal officials and demanded to know why Sanchez was not deported.

“Does that make any sense to you?” Johnson, R-Wis., demanded to know at a hearing. “Because I’ll tell you it doesn’t make any sense to the American public.”

State Sen. Jeff Stone, R-Temecula, said he would introduce legislation in Sacramento to require cities to comply with ICE detainer requests.

Sanchez pleaded not guilty Tuesday at his arraignment. His public defender Matt Gonzalez said the shooting appeared to be an accident.

In jailhouse interviews with two television stations, Sanchez said he found a gun wrapped in a shirt on the pier and it went off in his hands.

“This was an act of random violence, shooting an innocent victim in the back” prosecutor Dianna Garcia told the judge, arguing against releasing Sanchez on bail.

The judge set bail at $5 million, which Gonzalez said will keep Sanchez jailed pending trial.

A downcast Sanchez spent most of the hearing with his head bowed, appearing to fight back tear while the judge explained the charged to him. Sanchez was aided by a Spanish-language interpreter and entered his plea in Spanish.

Outside court, his attorney said Sanchez has a second-grade education and a non-violent criminal record of low-level drug arrests and immigration violations.

He could face life in prison if convicted.