Jewelers’ Security Alliance has issued burglary warnings to jewelers in Ohio and Michigan.

JSA reported that on Aug. 12 burglars in the Cleveland suburb of Parma Heights, Ohio, entered a retail jewelry store by drilling the lock out of the door, disabling phone lines, and taking two safes containing jewelry merchandise from the store.

JSA noted that this is at least the fifth time that alarms have been disabled in Ohio jewelry store burglaries this year.

“If your alarm system does not have line security, you are particularly vulnerable to this type of attack,” JSA said in an e-mail alert.

In Troy, Mich., JSA issued warnings about grab-and-run serial thieves. In the latest theft, on Aug. 8, a man asked to look at diamond rings in a chain retail jewelry store, JSA reports. He later returned and asked to see a specific 1.50 ct. white gold diamond ring. When it was removed from the display case, the man grabbed it and ran.

The suspect is described as a black male; 5 feet, 6 inches tall; with a circular scar on his left cheek. He may be accompanied by a female suspect, also black; 5 feet, 5 inches tall; with a tattoo on her right wrist and a second tattoo on her right forearm.

Police believe that these suspects may also be responsible for a grab-and-run theft of a high-end gold watch from a different retail store in Troy on July 30, and the theft of high-end eyeglass frames from a third store on Aug. 2 and Aug. 8.