Christopher Dorner, accused of plotting out revenge against former police colleagues and suspected of murdering three people, was seen in surveillance footage purchasing scuba gear two days before the killings occurred.

(PHOTO:Facebook/Christopher Jordan Dorner)Christopher Jordan Dorner, suspect in California cop shooting.

Surveillance of Dorner purchasing the gear in Torrance, Calif., on Feb. 1 was revealed Monday by TMZ. The former cop and Naval reservist, who served in an undersea warfare unit, was seen purchasing two yellow tanks and one black scuba tank in the video.

It appears that Dorner is having the two smaller tanks filled with air before he purchases a third.

The search for Dorner continued over the weekend, prompting Grammy officials to increase security at the awards ceremony. Police confirmed Monday in a Los Angeles press conference that they have received over 600 tips over the tip line.

Hundreds of investigators are following up on leads, Department Lt. Andy Neiman said Monday. On Sunday, officials announced a $1 million award for information leading to the arrest of Dorner.

"Our commitment is to finding Mr. Dorner and making this city safe again," Neiman said.

Police believe Dorner is behind two killings that occurred over a week ago and the shooting of four police officers last Thursday, one who suffered from fatal injuries. Before beginning the spree, Dorner left an online manifesto linked to his Facebook page, laying out plans of those he intended to kill while also addressing certain celebrities and implying that he would eventually take his own life.

In the manifesto, Dorner, a former LAPD officer, stated that his motive for killing other officers was fueled by growing racist view points within the force.

"The department has not changed since the Rampart and Rodney King days. It has gotten worse," Dorney wrote in the manifesto, which was published on Monday. He also alluded to a 2007 case where he charged a fellow officer with using excessive force on a suspect. His claim was investigated and inevitably resulted in Dorner being fired on the basis of making "false claims."