Some members of a Los Angeles County watchdog panel are calling on Sheriff Jim McDonnell to launch a thorough investigation into allegations of a secret society of deputies that brands its members with matching skull tattoos.

The revelation this week that a deputy admitted to getting inked two years ago as part of a ritual within the Compton station has raised concerns that deputy cliques, long part of a controversial agency subculture, have persisted despite the department's reform efforts, the Los Angeles Times reported.

Hernan Vera, who serves on the Sheriff Civilian Oversight Commission, said the deputy's admission in a lawsuit over a fatal shooting that he and as many as 20 others have the signature tattoos was "thoroughly disturbing,'' The Times reported.

"It's not the kind of culture that you want to foster in the 21st century Sheriff's Department,'' said Vera, a principal in the law firm Bird Marella.

McDonnell said that for the last year, the department has been examining deputy tattoos, logos and symbolism within the organization, but he hasn't launched a new investigation into the Compton station deputies. He said there is also a separate administrative investigation into the shooting, which may address the deputy's admissions.

"I'm not somebody from a generation where tattoos are accepted the way they are today,'' said McDonnell, who said he was unhappy when he found out a couple weeks ago about the deputy's admissions under oath, The Times reported. "I'm looking at what's behind it. Is it just body art? Is it something that reflects well on our core values?''

The department has a history of clandestine groups with names like the Regulators, Grim Reapers and Jump Out Boys that have been accused of promoting highly aggressive tactics and perpetuating a code of silence among members. Nearly 30 years ago, a federal judge said the Vikings club was a "neo-Nazi, white supremacist gang.''

The latest revelations, detailed this week by The Times, center on a deposition given in May by Deputy Samuel Aldama, who described under oath a tattoo on his calf featuring a skull in a military-style helmet bearing the letters CPT for Compton, along with a rifle, encircled by flames. He said he got the tattoo in June 2016, about two months before he was involved in the fatal shooting of Donta Taylor, The Times reported.