A 15-year-old Ukiah girl who was drinking alcohol with older friends was sexually assaulted and two young men were arrested, Mendocino County sheriff’s officials reported Wednesday.

The Ukiah girl didn’t know what had happened to her but sought medical help Monday when she found she had bruising and cuts to her arms and bruises on her neck, officials said.

Deputies were called to the Ukiah Valley Medical Center to investigate the apparent assault.

She said she’d gone to a friend’s Ukiah home Sunday because she’d lost power at her house due to the storm.

She told deputies she and friends there were drinking alcohol and she’d spent the night.

The teen said she didn’t know how she’d become injured.

An investigation determined two young men at the house who’d been drinking with her had sexually assaulted her, officials said Wednesday.

Deputies arrested Ukiah residents Adam Degrenier, 18, and James Morris, 20, on suspicion of several related counts including unlawful sex, oral copulation, sexual battery and child endangerment.

Bail was set at $75,000 for each.

Deputies also arrested Trevor Gunby, 20, who resides at the home. He was arrested on suspicion of child endangerment, contributing to the delinquency of a minor and an outstanding arrest warrant. His bail was set at $25,000.