The family of 18-year-old Andres Guardado are calling for an independent investigation after he was fatally shot six times by a Los Angeles deputy. His sister Jennifer Guardado spoke to NBC Los Angeles and says that she believes the department is trying to cover up her brother’s death.

“Even if this is the last day I breathe, I’m not holding this back because I feel it in my soul that my brother was murdered and this was covered up,” she said.

US Representatives Maxine Waters and Nanette Diaz Barragán have also joined the family in calling for an outside investigation. “Another day and another Black or Brown kid has been shot in the back by police,” they said in a joint statement. “These killings must stop. We demand it. The American people demand it.”

County Supervisor Mark Ridley-Thomas is asking for the Office of the Inspector General to intervene. “I firmly believe that an immediate and independent investigation must be conducted by the Office of Inspector General (OIG) into this matter and I urge the Sheriff’s Department to immediately and fully cooperate with this OIG independent investigation,” he said in a statement.

Guardado was working as a security guard at a local body shop in Gardena when he was killed on Thursday (June 18). Authorities say he was carrying a gun at the time of the shooting, a claim body shop owner Andrew Haney refutes. “I’ve never known him to carry a gun and had he had a gun, he wouldn’t have taken it out and pointed it at an officer,” Haney said.

Capt. Kent Wegener said in a press conference on Saturday (June 20) that the slain teen was talking to someone in a car outside the business. He “looked to the deputies” and “produced a gun” before reportedly running away. The deputies then chased Guardado to the back of the building, where where he was fatally shot six times. He died at the scene and authorities say they recovered a semiautomatic pistol at the scene. The family is now waiting for Guardado’s autopsy results.