ALBANY, N.Y. (CBSNewYork/AP) — The mother of Sean Bell – an unarmed man who was shot and killed by NYPD detectives in 2006 – called on Gov. Andrew Cuomo Thursday to establish a special prosecutor’s office under the attorney general to investigate such cases.

Valerie Bell, testifying before state legislators on criminal justice reforms, said families of 18 people killed by police wrote to Cuomo last month asking him to meet with them. They’re still waiting, she said.

The governor’s office did not immediately reply to requests for comment. Cuomo has proposed legislation to establish a monitor who would review similar cases where no indictment is handed up and could recommend a special prosecutor.

Valerie Bell said the families want to prevent others from suffering the same way they have. She cited last year’s killing of Eric Garner in a confrontation with police officers on Staten Island, where a video showed a police officer using an apparent chokehold on the unarmed man.

She said better police training may help, but officers should be punished for wrongdoing and that would have more effect.

“What do you have to give to the grand jury or the judge to show they did wrong?” she said. “Is there a law that they cannot go to jail?”

Three of the officers who fired 50 shots into the car that Sean Bell, 23, was driving in Queens — killing him and wounding two friends outside a nightclub — were later acquitted of manslaughter and reckless endangerment by a judge.

Yul-san Liem, co-director of the Justice Committee, said the families are asking Cuomo to use his authority under the law to appoint a special prosecutor in the attorney general’s office to investigate police use of deadly force. Many say a conflict of interest arises when a district attorney prosecutes the police that he or she works with all the time.

Testifying earlier, NYPD First Deputy Commissioner Benjamin Tucker said major felony crimes in the city have dropped 75 percent since 1993. He said a recent survey showed 72 percent of residents overall have a favorable view of the police, but acknowledged that’s not true in some minority communities that need them most.

He made a note of the execution-style shooting that killed NYPD officers Rafael Ramos and Wenjian Liu as they sat in their patrol car in Brooklyn back in December.

The department will be sending patrol officers to additional training that includes ways to talk to someone who is initially uncooperative and how to restrain someone without injuring that person or officers, Tucker said.

Concerning possible state measures, he said that proposals to install bulletproof glass in patrol cars isn’t prudent because the glass needs to be breakable in a crash, though bulletproof panels in car doors could be useful. He proposed a new misdemeanor for disclosing the personal information of a police officer for no legitimate purpose. The proposal is meant to prevent people from putting home addresses online and inviting harassment.

Judge Lawrence Marks testified about proposed changes in the closed-door grand jury process, noting most states don’t use it and simply have public preliminary hearings to consider criminal charges. He defended a proposal by Chief Judge Jonathan Lippman that would put a judge in grand juries investigating police killings and permit public disclosure of grand jury transcripts in cases of significant public interest. He said secrecy can be important to protect grand jury witnesses and their proposal would allow that.

Upstate Broome County District Attorney Gerald Mollen said threats and intimidation of witnesses is an “overwhelming” problem. The state’s district attorneys support concepts in Cuomo’s proposal. It would allow the monitor to see certain grand jury records, though not the public.

(TM and © Copyright 2015 CBS Radio Inc. and its relevant subsidiaries. CBS RADIO and EYE Logo TM and Copyright 2015 CBS Broadcasting Inc. Used under license. All Rights Reserved. This material may not be published, broadcast, rewritten, or redistributed. The Associated Press contributed to this report.)