Dimitri Herard, head of security at the Haitian presidential palace has been taken into custody as part of the investigation of July 7 assassination of President Jovenel Moise.
A close associate of Herard said he was detained Wednesday.
CNN said Herard failed to appear before a court inquiry ordered by the public prosecutor of Port-au-Prince because he had been summoned by police for questioning.
Moise was killed during a predawn attack on his private residence in a wealthy suburb of the Haitian capital that also left his wife, Martine, seriously wounded.
National Police Chief Leon Charles said 18 Colombians and two Haitian Americans have been arrested in connection with the attack.
Among those arrested was 63-year-old Christian Emmanuel Sanon, a Haitian-born man based in the U.S. state of Florida.
Police believe Sanon was the mastermind behind the plot to kill Moise.
Charles said Sanon arrived in Haiti on a private plane in early June with some of the Colombians.
An official with the U.S. Drug Enforcement Administration told VOA in an emailed statement that one of the suspects in custody was an informant.
A manhunt continues for several more suspects, including a man identified by The Associated Press as John Joel Joseph, a former senator in opposition to Moise’s Tet Kale party.
U.S. President Joe Biden has dispatched a special delegation to Haiti to assist with the investigation.
Moise’s killing has created a leadership vacuum in the troubled Caribbean nation.
He had named neurosurgeon Ariel Henry to the post of prime minister to replace Claude Joseph, who was serving in the post on an interim basis while also serving as foreign minister.
But Henry was not sworn in before the assassination, and Joseph has declared himself acting prime minister.
A commission made up of representatives of all sectors of Haitian civil society plans to meet Thursday to sign a political accord that will name a new president.
Joseph, as acting prime minister, had requested the United States deploy troops to Haiti to protect key infrastructure.
*Voice of America