FORT LEWIS, Wash. -- A Fort Lewis-based soldier is accused of knowingly infecting at least one man with HIV.

Staff Sgt. Ruben Gutierrez, 29, has been charged with criminal assault with sexual motivation.

The statement of probable cause states in April of 2007, a 23-year-old man told police he became infected with HIV after having sexual contact with Gutierrez.

The man said he was told by his doctor that he had been infected in the past few months, which was around the time he had been in contact with Gutierrez.

The man added that prior to being infected, he had tested negative for the virus as recently as January 2007.

The man's doctor asked him to provide the names of the partners with whom he had had unprotected sex in the past few months. When he did so, the doctor identified Gutierrez as a patient who had been diagnosed with HIV a year ago and told to abstain from any sexual contact.

The document states Gutierrez, in the presence of a witness, denied he was HIV-positive to his alleged victim prior to engaging in sexual acts.

When investigators later questioned Gutierrez, he admitted to having had sexual contact with the man, but said he had been honest about his HIV infection, the document said.

One man, who spoke to KOMO News on condition of anonymity, said Gutierrez knowingly infected him and at least four others, some of whom are soldiers.

"I think the sheer number of partners that he's infected reveals his intention," he said.

When he found out he was HIV-positive, the man said, his life turned upside-down.

"I was stunned. I thought that my entire world had collapsed. It took over a year to get back to a place where I feel good about myself," he said.

Gilbert Rengel, who said he's known Gutierrez for ten years, doesn't believe he would intentionally infect anyone.

"They're making him seem like a monster but he's not a monster at all. He's a good guy. He takes care of people. He does what he's supposed to do at his job," he said.

But Gutierrez's alleged victim said one has little to do with the other.

"I definitely have great respect for him and all of our soldiers but he should be aware that his actions are just as human as anybody else's," he said.

Citing his life's changed course and his high-maintenance health care regimen, the man said Gutierrez must be stopped before he infects someone else.

"The antiretrovirals that I take are upwards of $3,000 per month," he said. "You can't cry over spilt milk, but there's no reason for other people to have to deal with what I have."

A Fort Lewis official on Wednesday night said he did not have records on Gutierrez's case, but said he would alert the soldier's unit.