When violent crimes are reported on campus, police are required by federal law to notify the public. But officers from the Ohio State University Police are worried that few people are getting the message.

For the last four years, the Department of Public Safety at OSU has used an “opt-in” system in which crime alerts are sent only to those who have subscribed to receive the alerts via e-mail. But on a campus with more than 50,000 students, only 2,633 people receive these e-mails.

“I would expect more people to be registered users,” said OSU Police Chief Paul Denton.

In the wake of three crime alerts reported in the last week, Denton has received numerous calls from people asking why the alerts aren’t sent to everyone at the university.

The answer, Denton said, is that the opt-in system is simply what people wanted when the crime notification system was created. That preference may have changed, though, and the system may change as well.

The university’s Emergency Notification Committee will meet with vendors of mass-communication systems later this week to look into new technology and reconsider whether the opt-in system is still appropriate. The committee will make a decision after further meetings with vendors next week.

Although OSU Police issue about 18 crime alerts a year, Denton said, three were issued last week, sparking a response from university officials.

“In the past few days, two Ohio State women students have reported that they were victims of sexual assault, in unrelated incidents,” said Javaune Adams-Gaston, vice president for Student Life, in a campus-wide e-mail. “These crimes are terrible violations of the young women who were attacked, and they are reminders that no place is completely exempt from danger, even our own familiar buildings and grounds.”

Adams-Gaston encouraged students to use the university’s student escort service and to enroll in the crime alerts. That day, nearly 600 people signed up to receive the e-mails.

In the first of three crime alerts issued last week, a student reported that she was raped at 8:45 p.m. outside McPherson Lab on central campus.

On Friday, a student told police that he fended off a man wielding a knife who tried to rob him outside Howlett Hall on the agriculture campus west of Olentangy River Road.

Police issued another alert Friday reporting two similar thefts in February. In both cases, female students invited three men back to their residence hall and later realized that the men had stolen from them. In the second theft, one of the women reported she was sexually assaulted in Morrill Tower.

Readers of The Lantern commented on the newspaper’s Web site that they were concerned they weren’t notified after the rape was reported Monday.

“How come the University never sent out a crime report?” one reader commented on www.thelantern.com. “I would have never found out if not for my friends’ facebook statuses.”

Despite the confusion about the opt-in system, Denton said more people are reading the crime alerts than in recent months. In the first five days of March, the crime alert Web page has received 5,405 hits, while it received 7,512 throughout February and 5,617 in January.

In addition to the crime alerts, the university also publishes Buckeye Alerts when emergencies occur on campus.

“This could be used for such things as tornado, fire, explosion or certainly an armed person inflicting harm,” Denton said in an e-mail.

Those alerts can be sent via text message, phone call or e-mail — but are also sent only to those who subscribe online.