The motive for an alleged conspiracy to kill a Waco area woman involving two of the woman’s daughters and the boyfriend of one of the daughters was sexual abuse, according to an arrest warrant affidavit released Thursday.

“It’s a very twisted plot,” McLennan County Sheriff Parnell McNamara said.

Deputies arrested Shonna Manson, 28, Wednesday morning at the home of her mother, Deawathae Holder, on Meandering Way in China Spring.

Investigators searched the mobile home in which Manson was staying with her mother after making the arrest and seized three telephones, a folder of paperwork and letters, a purse, a money transfer receipt, two knives and Manson’s ID card, according to a warrant return.

McLennan County deputies later surrounded Manson’s boyfriend, Jason Maples, 36, at around 12:45 p.m. Wednesday as he got off of a bus from Orlando, Fla., at the Greyhound terminal in downtown Waco.

Authorities continued to look Thursday for Manson’s sister, Stefanie Price, who’s also implicated in the alleged murder conspiracy, according to the affidavit.

They're asking anyone with information about her whereabouts to call the McLennan County Sheriff's Office at (254) 757-5095.

The investigation that led to the arrests started on Monday after an informant told a Waco police detective about the alleged plot, the affidavit says.

The detective relayed the information to the McLennan County Sheriff’s Office and two county investigators talked to the informant, who told them that Manson arrived on April 7 from Florida to visit her mother.

She said Manson told her that she was going to stay with her mother “long enough to kill her,” the affidavit said.

“Shonna told (the informant) that her boyfriend Jason Maples was going to come to Waco on a Greyhound bus and when Deawathae and Shonna go to pick Jason up, they were going to Home Depot and steal merchandise and then take Deawathae somewhere and shoot her,” the affidavit says.

“Shonna told (the informant) that Stefanie Price had gotten a gun for Shonna to commit the murder,” the affidavit says.

Manson wanted to kill her mother for allowing her grandfather, Vernon Holder, who died in what was ruled an accident in 2014 at his home, “to molest her and her kids,” the affidavit says.

“Shonna also told (the informant) that Vernon didn’t die of an accident, that she killed him and made it look like an accident.”

Maples boarded a bus for Waco at 11:35 p.m. on Monday.

McLennan County investigators tracked him through five states and were waiting when he got off the bus early Wednesday afternoon.

Deputies surrounded him, and when he struggled, tackled him.

"We have to take total control of the situation as fast as we possibly can, not give the suspect any time to draw a weapon, get to a knife," said McNamara.

After the arrest, deputies recovered syringes and suspected heroin, McNamara said.

Manson was in the McLennan County Jail Thursday, charged with conspiracy to commit murder.

She’s also held on four misdemeanor charges.

Her bonds total more than $100,000.

Maples was also jailed, charged with conspiracy to commit murder, and named in unrelated Travis County complaints charging resisting arrest and possession of marijuana.

Other local charges are pending.

His bonds total $116,000.