It happened shortly before 10:47 a.m. Friday near Third Street and Temple Avenue in Bluff Heights, according to the Long Beach Police Department.
The suspect, described as a bearded, heavy-set Hispanic man between 35 and 45 years old and 5-foot-7 to 5-foot-9 allegedly told the victim he knew her son in order to get into her home. That's when police said he sexually assaulted her.
On Saturday, officers said they located the suspect, whom they identified as Kevin Parks, a 42-year-old resident of Long Beach, while he was getting into his car along Magnolia Avenue. When police arrested him, they also found a gun.
Parks was booked for multiple counts including rape by force and felon in possession of a firearm, and is being held on $1 million.
"The exploitation of our most vulnerable community members is abhorrent," said Police Chief Wally Hebeish. "While I remain troubled and saddened by this reprehensible act, I am thankful for the employees of the Long Beach Police Department and the numerous hours they spent working non-stop to identify and promptly arrest this suspect."
Police warned residents to always verify the identification of unknown people who come to the door, use a two-way communication or video system and report any suspicious activity.
City News Service contributed to this report.