PAWTUCKET — They met on MySpace.com. She told him she was 16. He told her he was 17.

They had sex, the police said.

She is 11 years old. He is 21.

Pawtucket police found out about the liaison when the mother of the Providence girl became concerned for her medical welfare and took her to Women & Infants Hospital on June 4. The hospital notified Providence police and they called Pawtucket police when they learned the man is from their city.

Otensi M. Dekargai was arrested Monday. He was arraigned on a charge of first-degree child molestation Tuesday in District Court, Providence.

The 11-year-old girl and the man had talked online for a few months before they met, the police said. In April they agreed to meet on Chalkstone Avenue in Providence, according to Pawtucket Lt. Daniel Mullen. The man picked the girl up on Chalkstone and drove her to Pawtucket where they allegedly had sex, Mullen said. Later, he gave the girl cab fare to go home, Mullen said.

The police did not disclose why she needed medical attention.

The girl identified the man through his posting on MySpace.com, Mullen said. Because she is 11 it does not matter if she consented to sex or that there is no allegation that force was used, he said. At her age she cannot consent, he said. It also doesn’t matter that she lied about her age. It is a crime to have sexual relations with an 11-year-old child, he said.

Mullen said that parents must monitor their children’s access to the Internet. He said computers should be in a well-used area of the home, not in children’s bedrooms. He advised parents not to allow their children to use the Internet unless they are home.

The number of incidents of crimes against children and young people who meet their predators through the Internet is increasing, Mullen said. In January, Pawtucket police arrested three men for allegedly raping a 17-year-old girl who met one of the men on MySpace.com. Mullen said that the Police Department considers the rise in Internet crimes so serious that it is sending detectives to a workshop on Internet sites used by young people.

Michael Healey, spokesman for the attorney general’s office, said that despite the increasing number of cases involving MySpace, not enough parents are “talking to their kids about who they are talking to on the Internet and the information they are posting. In so many instances kids don’t realize how much information they are giving up to people who might intend on enticing them to harm them.” The attorney general suggests that young people not post personal information such as an address or phone number, or school, or a picture.

tpina@projo.com