A two-month undercover investigation led police this week to arrest three men and seize more than 500 marijuana plants, eight pounds of processed pot, $45,000 in drug money and two assault rifles that had been made to resemble toy guns.

Following an anonymous tip, detectives targeted two San Leandro homes Wednesday -- one in the 14500 block of Maracaibo Road and one in the 2100 block of Marina Boulevard -- where marijuana was being grown and guns and cash were kept, police told the Oakland Tribune.

One of the more disturbing discoveries in the Marina Boulevard house were assault rifles apparently made to seem like toy guns, an officer said.

Police at the Marina Boulevard house found two partially assembled AK-47 assault rifles with orange plastic tips on their barrels, making the weapons look like toy guns. The colored tips are put on toy guns that otherwise resemble real weapons.

"It is frightening to know that AK-47 assault rifles capable of penetrating body armor worn by law enforcement officers were made to look like toys," said San Leandro police spokesman Lt. Robert McManus.