Rabies tests have come back negative on the gray wolf that is suspected in an attack on a teenage camper during the early hours of Aug. 24 near Lake Winnibigoshish.

The confirmation was made Wednesday by a laboratory at the Minnesota Department of Health.

The wolf was trapped and killed at the campground on Monday, about two days after the attack, and its carcass was sent to the Twin Cities for rabies testing.

Naturalists with the Department of Natural Resources (DNR) said Thursday that they can’t say with 100 percent confidence that the wolf is the one that inflicted the bites. They hope DNA testing will settle that question. The youth’s shirt, a potential source of wolf saliva DNA, and wolf muscle tissue have been sent to a laboratory at the University of California, Davis, for forensic analysis. The analysis expected to take several weeks.

Meanwhile, the U.S. Forest Service has reopened the West Winnie Campground, which had been closed since Saturday.

The 16-year-old camper, identified by the Bemidji Pioneer newspaper as Noah Graham of Solway, Minn., received stitches and rabies shots at a hospital in Bemidji and is recovering.

The nighttime incident is the first documented wolf attack on a human in Minnesota, according to the DNR. Naturalists have said they believe it was an anomaly; the captured wolf had jaw and tooth deformities that may have rendered it a poor hunter and made it dependent on people and campgrounds for food.

The University of Minnesota Veterinary Diagnostic Laboratory has conducted an initial examination of the wolf carcass. The results of additional tests will take several weeks, officials said.