Roark declined to say anything about the alledged's shooter's motive or his relationship to the couple or the New England Pentecostal Church.
"This does not seem to be a random event at this point", he said. Police said the shooter arrived at the scene after the wedding began.
The area has been sealed off with tape as ambulances and dozens of other emergency services, including fire trucks, are at the scene.
Pelham is located about 40 miles (64 kilometers) south of Concord, New Hampshire's capital. Luis Garcia was killed on October 1 at a house in the nearby town of Londonderry.
Lowell General Hospital in MA received one patient from the church shooting, who was then transferred to a Boston hospital shortly after noon Saturday, according to Angela Struck, director of public relations for the hospital.
The 60-year-old was killed earlier this month. Brandon Castiglione, 24, has been arrested in relation to the crime.
Roark said the New Hampshire attorney general's office would provide more details later.
New Hampshire Gov. Chris Sununu confirmed the shooting investigation and that law enforcement was on the scene.
Roark said the church had just received active shooter training from his department within the previous year.
The church was preparing Saturday for the noon celebration of life for Luis "Kiko" Alberto Garcia.