The youth, who cannot be named for legal reasons, was arrested at 11.30 pm in Rawai on Monday.
The German is accused of conspiring to sexually abuse two young boys together with 41-year-old British national Dax J Young, who was arrested at his house on Soi Laksila, off Phra Barami Rd in Patong, at 6 pm on March 6.
Police have identified two victims aged nine and 13 are still investigating to determine whether more boys were abused.
The two accused were presented at a press conference at Kathu Police Station at 4.30 pm yesterday led by Phuket Provincial Police Commander Apirak Hongtong and DSI officer Pol Maj Jatuporn Arunleaktawin.
Maj Gen Apirak said the German youth was renting a house with his mother in Rawai and has lived in Thailand for one year.
Mr Young had befriended the German, who spent a lot of time at the older man’s house near Wat Suwansiriwong School, Maj Gen Apirak said.
Mr Young set up soccer nets in front of the house and often invited boys from the school to play football with them.
They enticed the children into the house with the promise of sweets and video games, then sexually abused them, police said.
Some boys went once and did not return to the house, while others returned several times. The accused paid some of the boys sums of 200-300 baht after their visits, police allege.
The alarm was raised when teachers at the school noticed that some of the boys in their care were spending time at the house.
In February, the teachers told The Mirror Foundation of their suspicions.
The foundation, a non-profit development organization known for its work with children, informed the DSI.
The DSI coordinated with social workers during its investigation and arranged for psychologists to interview boys who had come into contact with the accused.
At least two said they were abused.
A search of Mr Young’s and the German youth’s home yielded as evidence a laptop computer, two digital cameras, a video camera, 128 CDs, three video tapes, two DVDs, a male dildo, name cards, a hard drive, a flash drive, as well as nine Japanese-style nude cartoon books.
The photographs featured underage boys naked and engaged in sexual acts.
On Monday, Kathu Police Superintendent Grissak Songmoonnark showed the media a dossier of evidence containing graphic images of a Caucasian man alleged to be Mr Young performing anal sex on a boy whose age was estimated at no older than 12.
Mr Young, who was born in Kenya but carries a UK passport, has denied the charges.
The German youth has confessed to the charges, however.
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