A 24-year-old man was arrested in west Salt Lake City after construction workers spotted him attacking a woman and called police.
Police said workers saw the man pull the noticeably intoxicated woman into an alley near 360 W. 300 South about 11:30 a.m. Thursday.
Suspicious, the workers followed and then allegedly observed the assault under way and called 911.
Police arrived and took the man into custody.
He was being held Friday without bail at the Salt Lake County Jail in suspicion of rape.