Melina Abdullah, professor and co-founder of BLM Los Angeles, on police commission hearing arrest

LOS ANGELES, Calif. (FOX 11) - Two women were detained Tuesday after an unknown powdery substance was thrown at Los Angeles Police Chief Charlie Beck during a police commission hearing.

Sheila Hines-Brim, who allegedly threw the powder, and Cal State LA Professor Melina Abdullah, who allegedly assaulted an officer as police cleared the room, were both arrested, according to authorities.

Abdullah is a leader of the Los Angeles arm of Black Lives Matter, and Sheila Brim, an aunt of Wakiesha Wilson, who died while in LAPD custody in 2016, according to LAPD spokeswoman Detective Meghan Aguilar.

Brim allegedly threw the substance toward Beck about 10:15 a.m. during the meeting at the LAPD's downtown headquarters, and some of it got onto the chief, Aguilar said. As she was walking away, Brim shouted, "That's Wakiesha,'' hinting that the substance may have been Wilson's ashes.

She was detained and later arrested on suspicion of misdemeanor battery on a police officer. Abdullah was detained and later arrested on suspicion of committing the same offense after she allegedly made contact with another officer.

Abdullah joined us on Good Day LA to share her side of what happened.

Some witnesses questioned whether the ashy substance was thrown or merely placed in front of the chief.

The commission meeting was adjourned and the room was cleared. Police and fire department hazardous materials crews responded, later determining the substance was not dangerous, Aguilar said.

Beck was examined at the scene, Aguilar said.

No injuries were reported and no evacuations were ordered.

"Today's assault was not only disrespectful to the Office of the Chief of Police, but more importantly to a process of community engagement that has been recognized across the nation,'' Beck said in a statement.

"Our police commission is the model for civilian oversight in every major city across the country, and is designed to invite productive discourse in a public setting. This only created chaos and fear for any Angelinos who wanted to voice their opinion about policing in our city.''

The origin of the substance was not immediately determined pending further testing, Aguilar said.

Wakiesha Wilson died while in LAPD custody in March 2016. Police said she was found hanging in her jail cell at the Metropolitan Detention Center, and the coroner's office ruled her death to be a suicide. Activists disputed the ruling, arguing that Wilson was not suicidal. They also faulted the LAPD for failing to notify Wilson's family of her death.

The city agreed late last year to pay Wilson's family nearly $300,000 to settle a lawsuit they filed over her death.

Detectives will present the Brim and Abdullah cases to the city attorney for the possible filing of misdemeanor charges.

Both women's bail was set at $20,000, police said. Abdullah was released around 6:30 p.m. and Brim about two hours later, according to sheriff's inmate records.

Aguilar acknowledged that police commission meetings are often heated and said the LAPD has no intention of "quashing'' such passion, but noted the department has a duty to maintain a safe environment for all attendees and participants.