The study was taken off the Rand Web site, the Los Angeles Times reported. The Los Angeles city attorney's office demanded a retraction in a letter Sept. 21, calling the report "highly suspect and unreliable."
Rand spokesman Warren Robak said an internal review was being conducted "expeditiously."
"As we've begun to take a look at the report, we decided it's best to remove it from circulation until that review is complete," he said.
The study examined crime rates in the 10 days before and after a medical marijuana ordinance took effect June 7, 2010. Many of the city's illegal dispensaries closed on that date, and researchers said crime rates went up in the neighborhoods where they closed.
The researchers suggested dispensaries might help cut crime by bringing additional security cameras and guards to the area -- along with additional police patrols -- by increasing foot traffic at night and by reducing street drug sales. But the city attorney's office, which -- in an effort to cut the number of pot dispensaries has been arguing that they increase crime -- pointed to some problems with the research techniques.