The trail was growing cold.
In September 2011, two men entered West Philadelphia's Lorena Grocery just minutes before its 8 p.m. closing. They shot and killed the store's owner, his wife and her sister, then fled with less than $700.
For months, Philadelphia Police detectives collected tips and ran down leads. They tried to piece together composites from grainy surveillance videos from a nearby school. Rewards were offered and the families of Porfirio and Carmen Nunez and Lina Sanchez pleaded for someone to come forward with information. Yet the killers remained at large.
Then in January, Homicide Captain James Clark decided to take a different tack: He put together an elite team containing two of the best detectives from each of his squads, under the leadership of a top supervisor, and gave them 30 days to make in-roads on the case.
He had arrests in less than that.
"It was nothing short of amazing how they brought this job in," Clark said.
New eyes on the case recognized similar robberies had taken place in other pockets of the city that summer. In one of the incidents, at a Southwest Philadelphia corner store, video cameras had captured clearer images of the robbers' faces. In another, in North Philadelphia, a clerk has been shot and there was ballistics evidence.
"They pulled video and ballistics and they started getting matches and identifying players," Clark said.
With the help of the Narcotics Division and Southwest Detectives, police launched massive drug sweeps through Southwest and West Philadelphia, seeking information about the slayings.
Officers eventually pulled in Ibrahim Muhammed, 31, for questioning after finding him with marijuana. Muhammed lived a block from the Southwest Philadelphia store. He was quickly arrested in connection with the murders at Lorena Grocery.
A short time later, his alleged accomplice, Nalik Shariff Scott, 30, was also taken into custody. Both men have been ordered to stand trial on murder and related charges. The District Attorney's Office has not said whether it would seek the death penalty.
"The job just really was good police work," said Clark, whose new top squad has since brought in six other high-profile homicide cases. For all homicide detectives, he said, "it's a real talent and passion they have ... They are just relentless."