BATON ROUGE, La. - The first message to Louisiana State University students went out at 12:14 a.m., describing a campus shooting with no suspects. "Please use caution!" it warned.

Hours later, no one had been arrested in the shooting deaths of two Ph.D. students from India, but officials decided not the close the campus. Many students had left for the holiday break, but with finals week wrapping up, many of those who remained did not have the option of skipping class.

Other colleges hit by shooters since the Virginia Tech massacre have responded differently. The University of Memphis canceled class the day after football player Taylor Bradford was shot, because authorities were uncertain whether it was a targeted or random attack. After two students were shot in September at Delaware State University, administrators ordered a swift shutdown.

LSU Chancellor Sean O'Keefe said he and police chose not to blockade the campus or reschedule tests after determining the students were slain in an isolated home invasion. Campus patrols were increased at the 28,000-student university, where many students already had headed home for the Christmas break.

"There was no evidence, nothing to suggest that there was a pattern here that would rapidly escalate. And as a consequence of that, a determination was made that we would not lock down the campus," O'Keefe said.

The bodies of Chandrasekhar Reddy Komma and Kiran Kumar Allam were found at Edward Gay apartment complex, on the edge of campus near a high-crime area of Baton Rouge. Each man had been shot in the head; Komma, 31, had been bound with a computer cable, and Allam, 33, was found near the door, said university spokesman Charles Zewe.

LSU's campus would be difficult to block off. Its many entrances are not gated, and at least two major city roads run through the campus. O'Keefe, who led NASA during the space shuttle Columbia disaster that killed seven astronauts in 2003, said the university took many precautions to notify students about the shootings but felt a campus shutdown was unnecessary.

After the killings, LSU officials sent a campus-wide alert via e-mail and voicemail messages and posted a message on the university's Web site. But at least one of the LSU notification systems, a text-messaging alert system put in place after the Virginia Tech shootings, failed to notify all 8,000 students who signed up.

"There haven't been any" messages, said Shenid Bhayroo, a graduate student in mass communication who said he signed up for the system days after it was set up. "Many of us took comfort that LSU implemented this system, so it's worrisome that the system doesn't work."

The problem with the text-message service provider was corrected by afternoon, the university said in a brief news release.

LSU officials sent out their first campus-wide alert more than an hour and a half after the shootings.

Komma, a biochemistry student, had been visiting Allam, who was in the chemistry program. Allam's pregnant wife called 911 after finding the men dead, said Srinivasa Pothakamuri, a friend of Komma.

Zewe said police were searching for three men seen leaving the area. O'Keefe said nothing appeared to be stolen from the apartment, leaving police unclear about a motive.

The complex has a tall fence separating its 288 residents from the off-campus neighborhood, but the apartments have no gates or surveillance cameras.

The killings were the first on campus in more than a decade, but Edward Gay resident Omer Soysal said attempted break-ins and holdups are common at the apartments, where nearly all the residents are international students.

"When it is dark, I tell my kids: 'Don't go outside,"' said Soysal, 37, a third-year doctoral candidate in computer science.

Less than one-third of the student body had even signed up for the cell phone notification, though O'Keefe said university officials had stressed the need to do so after Virginia Tech.

"Registration spiked at one point, as I recall, over the summer and then trickled off," O'Keefe said. "This horrific incident is yet another reason why it is really a very good idea to register for the system, and we will again redouble our efforts."

The efforts will run into trouble with students like Cameron Hanover, a senior in political science, who said he didn't sign up and neither did any of his friends.

"I didn't want them to have my phone number. It's a privacy issue," he said.

Associated Press writers Mary Foster and Doug Simpson contributed to this report.