Long awaited BART shooting trial set to begin

After 18 months of delays and legal wrangling, the trial of a former Bay Area Rapid Transit officer charged in the fatal shooting of an unarmed man is set to start this week in Los Angeles.

Defense attorney Michael Rains is expected to argue Johannes Mehserle inadvertently pulled out his handgun instead of his Taser when he shot Oscar Grant on a transit station platform in Oakland on New Year's Day 2009.

Mehserle has pleaded not guilty to murder.

Observers say Mehserle's legal team is building momentum heading to trial, with a judge recently ruling that Grant's criminal record could be introduced. A video expert will also be allowed to be called by the defense.

Prosecutors contend Mehserle intended to shoot Grant and that he used his weapon because officers were losing control of the situation.

The trial is expected to last a month.

Copyright 2010 The Associated Press.