A woman who received threatening phone calls for months traced them to convenience store pay phones, helping police find the man making the calls, who was convicted this week of stalking.

Laurie Russo started receiving the calls in April from an unidentified man and called police, she said Friday. She took other security measures including moving in with a friend for a while.

"It was incredibly scary," said Russo, who lived alone. "You feel so violated and you are always looking over your shoulder."

Russo began keeping records of the calls. She used her caller ID and phone company traces to find that some came from convenience stores' pay phones. She drove to the stores, asked clerks for help and made a spreadsheet of store locations with pay phone numbers.

After getting a call Aug. 19, she matched the number to a store and called it, where clerks described a man who used the pay phone and got a license plate number. Police traced that to George Bishop, 68, of Cincinnati, a political science professor on leave from the University of Cincinnati.

Police found store video of him, The Cincinnati Enquirer reported. He was indicted on a count of menacing by stalking and pleaded no contest to the charge Thursday, his attorney Thomas Heekin said. Heekin said Bishop suffers from acute alcoholism and will be getting treatment.

"He is genuinely remorseful and devastated by his conduct, Heekin said.

Bishop is to be sentenced Feb. 2 and could get up to 18 months in prison.

Russo and Bishop didn't know each other and it's not clear why he targeted her.

A message seeking additional comment was left Friday at the Hamilton County prosecutor's office.

Bishop remains on leave from his job, University of Cincinnati spokesman Greg Hand told the Enquirer.

Russo says she hopes that by not letting herself be intimidated, she might have helped others in similar situations.