Days before Ibrahim Muhammed and Malik Scott were charged with killing three people in a West Philadelphia bodega in 2011, police announced that they had connected the crime to two similar armed robberies.

Now, five years after the killings, those robberies (one at a bodega on Reedland Street in West Philadelphia, the other on North Gratz Street in North Philadelphia) have become centerpieces of the prosecution's case - and of the defense's as well.

Prosecutors say a video from the Reedland robbery helped investigators recognize Muhammed and, eventually, elicit a confession from him.

Muhammed's and Scott's defense attorneys, who called their first witnesses Tuesday, say they will show the men were not involved in any of the robberies, and thus could not have committed the murders.

They say the prosecution's case hinges on mistaken identity and a false confession from Muhammed.

In cross-examinations, they have challenged witnesses on their descriptions of the men who shot to death Porfirio Nunez, 50; his wife, Juana, 44; and his sister Lina Sanchez, 48, in a robbery at Lorena's Grocery, 850 N. 50th St., in September 2011.

Prosecutors say Scott confronted the couple's daughters at the cash register, then shot Porfirio Nunez when he tried to intervene. They say Muhammed killed Juana Nunez and Sanchez as they tried to hide in the back of the store.

On Tuesday, defense attorneys called to the stand a former Temple University student who was robbed in a North Philadelphia bodega in July 2011.

Amber Creamer testified that she and several friends had been buying soda at a bodega at 2000 N. Gratz St. when two men came into the store and one pointed a gun at the cashier. She said she and her friends dashed to the back of the store, where a second man pointed a gun at them and demanded her friend's wallet and phone. She said they heard gunshots.

Police said the cashier was wounded in the robbery.

She and her friend Jalal Aljuwaie told police that day that the gunman had a gap between his teeth.

Muhammed, the defense pointed out, has no such gap.

It was one of a series of arguments the defense has made about eyewitness testimony in this case - in the last week, defense attorneys have contended that witnesses' descriptions of the killers' facial hair and heights do not match those of their clients.

"This case is a primer on the vagaries and foibles of accurate identification," defense attorney Jack McMahon said in his opening arguments last week.

The defense will continue to call witnesses throughout the week.

215-854-2961 @aubreyjwhelan