Calif. Teen Suspected of Killing Sister Over Laundry Reward offered for the 14-year-old, who police say is armed and dangerous.

Jan. 25, 2014 -- Oakland, Calif., police are searching for a 14-year-old boy in connection with the shooting death of his 17-year-old sister, which reportedly happened following an argument the pair had over how she did the laundry.

The Oakland Police Department offered a reward of $10,000 for any information leading to the arrest of Mario Toliver Jr., who is suspected of fatally shooting his 17-year-old sister, Justice Toliver, on Thursday in their grandmother's apartment in Oakland's Chinatown neighborhood.

Police told ABC News today that the teen was still at large and the investigation was continuing.

"We have not recovered the firearm that was used in this homicide so that is a concern not only for law enforcement but for our community as well," police spokeswoman Johnna Watson told ABC station KGO-TV in San Francisco.

Shortly after noon on Thursday, security cameras caught Mario Toliver carrying a gun as he walked down the hallway of the apartment block's fifth floor where he and his sister lived with their grandmother, police said.

Video then captured the 14-year-old fleeing through an emergency exit leading onto Franklin Street, theu said.

Police have asked the family to appeal to Mario to turn himself in.

"We love you; we're hurting just like you are hurting, please do the right thing," the siblings' grandmother, Wanda Brown, said.

The boy has been described as having dark hair, brown eyes and is five feet, five inches tall, weighing 140 pounds.

The siblings' cousin, Marianna Gaston, 22, told KGO-TV she was told the pair were arguing because Justice had reportedly bleached some of Mario's clothes, but thought it was a "joke" when she heard the boy had shot his sister, who leaves behind a 3-year-old daughter.

"Why would he kill her over that?" Gaston asked. "Nothing makes sense. It doesn't add up."

Police are asking anyone with information about the crime to call the Oakland PD homicide division at (510) 238-3821.