Speaking at a press conference on Monday, Los Angeles Police Chief Charlie Beck defended the officers who shot a homeless man to death on the city's skid row yesterday, offering visual evidence he says supports their version of what he called "an extreme tragedy."

"It appears to me officers acted compassionately," said Beck, "up until the time when force was required."

According to Beck, a review of preliminary evidence in the ongoing investigation shows the man, reportedly known by the street name "Africa," "forcibly grabbed" an officer's holstered pistol.

Beck displayed several pictures in support of this claim, including a still from the widely-circulated bystander video and a photo of an officer's jammed pistol.

"As you can see, the slide is partially engaged and a round has been partially ejected and fouled the firing chamber. This is indicative of a struggle over the weapon," said Beck. "There's also a screen grab from a privately-taken video. If you examine that, it appears that the suspect's hand is reaching for the officer's waistband in the area where his pistol would be located."

According to ABC News, a police source says the investigation could take up to five months to complete.

[Images via ABC.com]