MOSCOW — A Russian investigative journalist was placed under two months’ house arrest in Moscow on Saturday, accused of selling drugs.

The reporter, Ivan Golunov, 36, was on his way to a meeting with a source on Thursday when he was detained, with illegal drugs found in his rucksack, according to the police and his employer, the online news portal Meduza, based in Latvia.

A lawyer for Mr. Golunov, who is known for investigating corruption among Moscow city officials, said he believed officers had planted the drugs, and accused them of beating Mr. Golunov as well.