With a four-agency task force finding itself in a blind alley, the Federal Bureau of Investigation has been roped in to track down the killers of two Indian students at a Louisiana State University apartment three days ago while two senior Indian diplomats visited the campus and reviewed the probe.

First Secretary Alok Pandey from Indian embassy in Washington and Consul K P Pillai from the Consulate in Houston met Chancellor Sean O'Keefe, investigators as well as community leaders and students in Baton Rogue and assured all help to the families of victims.

"The investigation is being conducted by a taskforce and they are being assisted by the Federal Bureau of Investigation," Keefe told a television channel.

While investigators were focusing on three to four suspects described as 'black men,' they admitted that they have not established a motive so far. Also their problems are likely to be compounded as students, some of whom could be potential witnesses, have started leaving the campus for the Christmas holidays after the exams ended on Saturday.

"We are up against a rapidly ticking clock in terms of identifying potential witnesses," said Baton Rouge Police chief Don Kelly, a spokesman for the task force investigating the Thursday night killings of Kiran Kumar Allam, 33, and Chandrasekhar Reddy Komma, 31, both from Andhar Pradesh.