KNOX, Maine — Though it is difficult to cite drivers under the state’s 2011 law against texting while driving, a Unity woman who admitted to the practice was issued a citation for it last week, according to police.

Sarah Z. Wentworth, 22, came to police attention at about 8 p.m. Thursday, when another driver on Belfast Road in Knox called to report that her vehicle was weaving back and forth on the road, Chief Deputy Jeff Trafton said Monday. A deputy investigating the complaint saw Wentworth’s car cross the centerline twice, and he stopped her to ask what was going on.

“She said she was tired, and she was texting,” Trafton said.

Ordinarily, texting drivers are hard to catch in the act, he said. Police request cell phone records during the investigation of serious crashes to see if they had been texting, but it’s challenging to see if that’s what someone is doing while behind the wheel.

“You can’t tell what they’re doing inside the vehicles. It’s tough to see what’s going on,” he said.

Wentworth was issued a $135 citation for texting while operating a motor vehicle.