New Hampshire State Police Major Crime Unit is involved in the investigation and the counter terrorism unit of the New York Police Department said it is "closely monitoring the shooting incident" at the church.
Choate was taken to the hospital in serious condition and McMullen is in good condition, officials said. He will be arraigned in Hillsborough Superior Court Tuesday.
The Pelham police chief, Joseph Roark, said no fatalities were reported in the shooting at New England Pentecostal church in Pelham. He didn't know if people who subdued the shooter were trained the same way but "I think that is a standard that is being taught now to address the threat".
The Pelham Police Department provided active shooter training to members of the church within the past year, Roark said.
Three people have been hospitalized, including two people for gunshot wounds and a third person for minor injuries, Roark said, adding that police had recovered a handgun from the scene.
A memorial service for Luis Garcia was set to be held at the church at noon Saturday.
Roark did not offer a motive for the shooting.
Pelham is approximately 40 miles south of Concord, the state's capital. Brandon Castiglione, 24, has been charged with second-degree murder in his death. His obituary said he was a minister at the church.
This is a developing story, originally published by New Hampshire Public Radio, with additional reporting from WBUR.
Those planning to attend the Garcia service were shocked by the shooting.