Officer Fredys Castro-Rivas spotted the little girl’s silhouette just beyond the basketball court in the Lewisdale neighborhood park Monday, her hand enclosed in that of an older man. As he rushed toward the pair, the man let go and tried to walk away.

That, authorities say, is how Prince George’s County police were able to catch a man suspected in the sexual assault of one young girl and attempted sexual assault of another in the Lewisdale area. Castro-Rivas said that he detained the man, 25-year-old Charles Asuming Amofa, and police charged him in connection with Monday’s incident and a similar one last month.

“I could only think, ‘What if my daughter was to be missing?’ ” Castro-Rivas said, recalling how the girl told him “I want my daddy” as her eyes filled with tears. “What would I do in this case?”

The chain of events that led to Amofa’s arrest began about 1:30 p.m. Monday, when a 6-year-old girl’s father approached Castro-Rivas in the Value Village Thrift Store on University Boulevard, authorities said. The father told Castro-Rivas, who was working an off-duty security job, that he had lost sight of his daughter for no more than a minute and that now he could not find her.

Castro-Rivas began to drive around the Lewisdale area in search of the girl, roughly tracing the route she might use to walk home. He said the father had showed him a cellphone picture of his daughter, and her description was etched in his mind.

Charles Asuming Amofa was charged with kidnapping, first- and second-degree sex offenses and other related counts, authorities said. (Courtesy of Prince George's Police Department)

About a quarter-mile away in the park, Castro-Rivas said he spotted the silhouette of a child and a man. He said he rushed to separate the two and called for backup.

“It’s only one in a million,” Castro-Rivas said of finding the girl.

Detectives soon learned that the man had lured the girl from the store by saying he knew her father and had a toy outside to show her, said Prince George’s County police Detective Luis Machicote. He said that although the man was with the girl for less than 30 minutes, he had engaged in some type of inappropriate sexual contact with her near the park’s swing set.

Amofa was charged with kidnapping, first- and second-degree sex offenses and other related counts, authorities said.

Machicote said Amofa also admitted to detectives that he was responsible for a similar incident July 9, luring an 8-year-old girl from the same thrift store so she could “meet his manager.” Once outside, the man led the girl to a nearby vacant house, where he tried to grab her and touch her inappropriately, Machicote said.

Machicote said the girl escaped and ran back to the store just as her parents were telling a police officer that she was missing.

Julie Parker, a Prince George’s police spokeswoman, said the 6-year-old girl’s father gave a statement to authorities, thanking them for finding his daughter but saying he wanted to “erase what happened.”

“My daughter — we always know something’s special about her. She’s very thoughtful and understanding,” the man said in the statement. “She’s still being herself. She’s being energetic. She did mention that something did happen to her, but she doesn’t let that change the way she acts. She told me, ‘Daddy, I’m not thinking about that.’ ”