WEST LAFAYETTE, Ind. -- Investigators will use boats to search the Wabash River on Thursday as they look for a missing Purdue University student.

The search is widening for Wade Steffey, 19, a freshman from Bloomington, 6News' Julie Pursley reported.

Police have a new map of where Steffey's cell phone was last tracked. The new information indicates the area is larger than originally thought, extending north and east of Ross-Ade stadium.

The Wabash River has been searched before, but water has receded since the previous search.

Steffey was last seen after leaving a fraternity party just after midnight Jan. 13. His cell phone continued to emit a signal for five days after he disappeared.

Investigators will also employ an Indiana State Police helicopter to search from the air if weather permits.

More than 700 volunteers have joined in the massive search over the last week-and-a-half. Police are asking anyone who might have seen something, or found someone's personal effects, such as clothing or a wallet, to call Purdue police at 765-494-8221 or an anonymous tip line at 765-496-3784.

Steffey has short brown hair and brown eyes. He is 5 feet 10 inches tall and weighs about 150 pounds.