Police said Roger Self took his family into the Surf and Turf Lodge in Bessemer City.
Once they were seated, he then excused himself, went out to his vehicle and drove it at a high rate of speed into the area where they were sitting just after noon on Sunday.
Self's daughter Katelyn, 26, was one of the victims killed; she was a Gaston County sheriff's deputy.
The other victim was identified as Amanda Self, Roger Self's daughter-in-law, according to the family's pastor, Austin Rammell.
Other family members were also injured, according to police, including Amanda Self's 13-year-old daughter and Roger Self's wife, Diana. They are expected to recover.
Self was arrested and charged with two counts of first-degree murder. Rammell said Self was suffering from mental illness. He considered Self to be one of his best friends.
"This is totally opposite of who he is," Rammell said.
Rammell said he saw the entire family in church Sunday morning, just a couple of hours before the horrific attack.
"I'm just trying to encourage them," Rammell said. "This was not a conscious act by their father and they know that."
The community is also feeling the loss.
"Tragic, tragic loss of life," Gaston County Sheriff Alan Cloninger said. "I'm asking people just to keep the family in your prayers, and the Sheriff's Office, because we're suffering right now."
WSOC and the Gaston Gazette contributed to this post