Authorities say they do not think a recent armed robbery at a south Forsyth restaurant is related to a string of violent crimes that ended earlier this month in the fatal shooting of a security guard.

According to a Forsyth County Sheriff’s report, three suspects held up a Waffle House on McFarland Parkway about 1:15 a.m. Thursday.

Witnesses told authorities two black men, one of whom had a handgun, demanded cash out of the register while a third man blocked the doorway.

They forced a customer inside the eatery to the ground, the report shows, and grabbed money from the register, as well as cash and credit cards from the man.

The suspects also took a cell phone from a woman inside the restaurant before leaving on foot.

Sheriff Ted Paxton said investigators don’t think the suspects are connected to those charged with the Sept. 5 armed robbery at Ingles on Canton Road.

“There’s nothing to indicate any relationship at all,” Paxton said.

In the Ingles case, 37-year-old David Casto of Winder was shot to death.

Four teenage suspects, two of whom are recent Forsyth County high school graduates, have been charged with armed robbery and murder in connection with the incident.

Sheriff’s Lt. Col. Gene Moss said authorities are checking for similarities between the Waffle House robbery and others in the state.

“It’s taking some time, basically, to get with those other jurisdictions and review the video and do some comparisons, which we’re going to do,” Moss said. “So at this point we’re not able to say that they’re linked.”

Moss said investigators think, based on information they’ve gathered, that the suspects in the Waffle House incident headed south in a vehicle on Ga. 400.