The photos on Julie Curtis' desk are hard to look at: a decapitated Labrador mix, a headless rottweiler, a pit bull puppy that appears to have been strung up with twine.

As the only animal cruelty investigator for the Humane Society of Huron Valley, Curtis started her day Monday staring at those grisly photos and sorting through the 200-odd messages left with her -- hoping one would produce a tip on who might have killed seven dogs, all believed to be pets, found over the last two weeks in Washtenaw County.

And she's trying to sort out an odd fact: none of the dogs have been linked with those reported missing in the region, suggesting that whoever is killing them is bringing them in from outside the area.

Other than that, she said she has no strong leads, no suspects.

"I'm exhausted, I'm drained and, at this point, I'm angry," Curtis said. "But I'm determined. I'm going to find who did this."

Since January, authorities have found nearly 40 dead domestic and wild animals -- some decapitated, some skinned -- within a 3-mile radius of Superior Township, including coyotes, foxes and deer. On March 16, they started finding dogs. The most recent find, on Sunday, included the tied-up pit bull puppy and a cocker spaniel that had been shot in the back of the head.

The area is largely wooded and rural, with houses spaced far apart and country roads traversing the hilly region.

"It wouldn't be hard to dump an animal here at night without anyone noticing," Curtis said.

The finds have unnerved the community. Linda Morgan, for one, isn't taking any chances. Living on Leforge Road near Geddes, Morgan, 41, said Monday that she started bringing her two dogs inside before dusk last week. She owns a rottweiler, Candi, and a German shepherd named Star.

About a half-mile away, authorities found the dead pit bull and spaniel on Sunday.

"What I can't understand is how someone got their hands on these dogs in the first place," she said. "Maybe with a tranquilizer gun. It's really sick."

Her husband, Terry Morgan, 43, said: "Jeffrey Dahmer started out killing animals."

On Monday, the high-energy Curtis spent much of the day answering her near-constantly ringing phone, talking to people who thought they might know something of use. Many, she said, called to tell her about people they thought might be capable of killing the dogs.

She stopped to run outside to do TV and radio interviews, trying to get the message out: No matter how insignificant you might think the information is, please call.

"I've dealt with a lot of maniacs," said Curtis, who has been a certified animal cruelty investigator for six years after attending the University of Missouri. "I've dealt with bestiality. This ranks at the top, with the worst I've seen."

Some raised concerns that the animal deaths could lead to worse crimes. Kelly Schwartz, the Huron Valley Humane Society's director of operations, said studies have shown that someone who hurts or mutilates animals is 50% more likely to commit other crimes.

Cmdr. Dave Egeler of the Washtenaw County Sheriff's Department cautioned people not to worry, however, saying there is no evidence that people should fear for their safety.

Under state law, a felony animal cruelty charge can result in a prison sentence of up to four years and a $5,000 fine.

Peter Wood, deputy manager of Animal Cruelty Issues for the Humane Society of the United States in Washington, D.C., said Monday he has never heard of anything resembling the Superior Township cases. "Anyone who would be doing these types of crimes we would consider dangerous, and residents should be concerned," Wood said.

Earlier this month, Ryan Troyer, a 22-year-old Folsom, Calif., man was arraigned on animal cruelty charges after El Dorado County sheriff's officials accused him of strangling 10 goats at a ranch.

In 2004, seven Wisconsin high school students were arrested after various animals were trapped in the woods and beaten to death.

Contact BEN SCHMITT at 313-223-4296 or bcschmitt@freepress.com. Staff writer Stan Donaldson contributed to this report.