A top Sri Lankan police official was arrested on Thursday over a suspected plot to kill President Maithripala Sirisena, police a spokesman said.
The alleged plot briefly threatened to cause tension between Sri Lanka and India, after an Indian newspaper report that Sirisena had accused India's intelligence services of involvement - a claim New Delhi and Colombo have both denied.
"The Criminal Investigation Division of police today arrested Nalaka De Silva after five days of questioning him," police spokesman Ruwan Gunasekara said.
Gunasekara said Silva was charged with plotting to kill the president, several senior police officials and a former defence secretary.
Magistrates ordered Silva, a deputy inspector general of police, be detained until Nov. 7.
A police informant made the allegations against Silva in a news conference. Investigators are seeking access to deleted data from the informant's mobile phone with the help of Huawei after a court granted permission to request the company's help.
Silva's lawyers were not immediately available for comment.