DALLAS >> Dallas police say they could conclude their domestic violence investigation of Cleveland Browns quarterback Johnny Manziel by late next week.

Police spokesman Maj. Midge Boyle said Saturday that investigators have reviewed medical records provided by Colleen Crowley, Manziel’s ex-girlfriend. Crowley told police Manziel hit her and dragged her into a car in late January.

Manziel hasn’t been charged, but a judge has issued Crowley a protection order against him.

Police haven’t interviewed Manziel, but spoke to several other witnesses. Boyle says police want to have their strongest case against Manziel before speaking to him.

Some defense lawyers have questioned whether Manziel is getting special treatment and another suspect facing similar allegations might already have been arrested. Boyle said the detective investigating the allegations “hasn’t gotten all the facts yet.”

“She’s still putting the case together,” Boyle said. “It’s been two weeks since this investigation started, and it is high-profile.”

“As soon as we have something pertinent to put out, we will let you know,” she said.

A Heisman Trophy winner at Texas A&M, Manziel has had several incidents of trouble in the NFL. The Browns have indicated they will release him next month.

Crowley said in an affidavit filed with the judge who issued the protective order that Manziel hit her so hard that she temporarily lost hearing in one ear.

In the affidavit, Crowley says she and Manziel had a confrontation in his Dallas hotel room around 1:45 a.m. Jan. 30. She says that after hitting her, he threatened to kill himself as he drove her to Fort Worth.