A Philadelphia lawyer is facing a mandatory 10-year prison sentence after being convicted of operating a sizable and sophisticated marijuana-growing operation in North Philadelphia.

Richard K. Creamer, 38, practiced real estate and corporate law in Northern Liberties. In October 2007, Creamer and James Alberts, a South Philadelphia contractor, bought a warehouse on the 2300 block of North American Street, said Assistant U.S. Attorney Joseph T. Labrum III.

Creamer and Alberts, 37, had worked together before, buying distressed properties and selling them for profit. But when Creamer learned that Alberts was grossing thousands of extra dollars a month with a marijuana operation at Third and Tasker Streets, the Temple University law grad wanted in.

Alberts was initially apprehensive, but relented, Labrum said.

"It was his chance to do his best-ever grow and make even more money," Labrum said. "He couldn't have done it without Creamer's contribution."

According to Alberts, who testified at Creamer's trial in federal court, they spent $100,000 to renovate the structure to create a high-tech marijuana farm on the second floor, Labrum said.

From March through June 2009, gardeners harvested 20 pounds of high-grade cannabis a month, Labrum said.

Creamer's share ranged from four to five pounds, which the gardeners would put in his office across the hall or deliver to his house, Labrum said. Creamer then handed off the weed to his brother, a New York City disc jockey, to sell, Labrum said.

Creamer and Alberts began to dream big. On July 2, 2009, the partners flew to the West Coast and signed an agreement to buy a 40-acre tract in Northern California they intended to use as an outdoor cannabis farm.

Two weeks later, DEA agents raided the Philadelphia warehouse and arrested Alberts and eight others. The agents found more than 1,600 marijuana plants growing under 1,000-watt sodium lights in three cultivation rooms.

Creamer canceled the Northern California deal, Labrum said, claiming he had just learned his business partner was involved in criminal activity.

Creamer was convicted Thursday of conspiracy to manufacture 1,000 or more marijuana plants and maintaining a place for manufacture of controlled substances. Sentencing is scheduled for May 23.

Labrum said Alberts also pleaded guilty to similar charges and was awaiting sentencing.

Attorneys for Creamer and Alberts could not be reached for comment.