The past participle of "to search (for)" is "searched."
You are mistakenly confusing it with the past participle of the verb "to seek," which is indeed "sought."
No one in the article was "seeking" Mr. Sands. They were "searching" for him. Hence, they "searched" for him.
NOT: They "sought" him.
Regards,
Sought
Aw the hell with it, the guy's missing!
CC