Last Updated at 12:08 p.m. EDT
A clearer picture of the finances of Melanie and Byrd Billings emerged Thursday revealing the murdered couple may have had money problems.
Meanwhile, authorities continued investigating the precisely executed, deadly break-in at the victims' Florida Panhandle home, with the Drug Enforcement Administration confirming their involvement in the case and police arresting an eighth suspect. Police are also still seeking at least one more accomplice who they believe failed his assignment to disable the house's surveillance system.
Court documents show the Billings, who were known for adopting 13 children with special needs, sued their own adult son for child support in 2008 after they took in his daughter - their granddaughter - in 2006, reports CBS News correspondent Terrell Brown.
They also had asked for a $50,000 life insurance policy for the then-18-year-old girl, with themselves as the beneficiaries.
Escambia County Sheriff David Morgan told CBS' "The Early Show" that the police have not investigated the Billings' finances as they've searched for their killers.
The DEA has also been investigating the murder from the beginning. Their interest - possible drugs and money laundering, though officials won't say who they're probing, reports Brown
Other federal agencies are also involved in the case. The Bureau of Alcohol, Tobacco and Firearms is helping trace the weapons used in the attack and the FBI is working to enhance the security video retrieved from the house.
Morgan once again denied having knowledge of any federal investigation.
Footage taken by the cameras helped lead investigators to the suspects in last week's shooting deaths. The videos showed masked men - some dressed as ninjas - slipping into front and back doors at the home.
Police on Wednesday arrested an eighth suspect, 47-year-old Pamela Long Wiggins, charging her with accessory after the fact to felony murder, Morgan said. Seven others have also been charged in the killings.
Police do not believe Long, the eighth arrest, was present at the murder scene but do suspect she may have personal ties to the alleged mastermind of the attack - Leonard Patrick Gonzalez Junior, reports Brown.
CBS News obtained a marriage license from December listing Long as the bride, with Gonzalez as a witness.
Police are still seeking two more persons of interest, Morgan told "The Early Show."
"Sadly, no, we do not feel that this is the end," he said.
Morgan said the suspects spent 30 days training for what was a precisely executed break-in, save for the failure to turn off the couple's camera system. Before the crime, the extensive surveillance system was used to monitor the children.
"The execution was basically flawless," Morgan said. "The one gaping hole that would not have made this a perfect operation, if you will, was the fact that the surveillance system was not disabled. I guess the question was why was it not?"
Morgan said an accomplice was assigned to turn off the cameras, possibly remotely, but never did - and the men who broke in apparently didn't know that. Morgan said authorities are looking for another person of interest who may have been the one assigned to turn off the system, though he did not identify that person.
The surveillance videos led investigators to a red van used as a used as a getaway car and eventually to the suspects, a loosely connected group of mostly day laborers who knew each other through a power washing business and an auto detailing operation.
They were in the nine-bedroom house for just four minutes and on the property for 10, Morgan said.
Morgan said the suspects took a safe from the house, though he would not say what was in it or what else was taken. Authorities have said the main motive was robbery, though there may have been others.
He said earlier that Wiggins is a friend and landlord to the 35-year-old Gonzalez Jr., whom Morgan described as a "pivotal person" in organizing the break-in. Gonzalez, who's charged with murder, proclaimed his innocence in court Tuesday.
State Attorney Eddins said the day before Wiggins' arrest that he will ask a grand jury to indict the suspects on first-degree murder charges. The male suspects range in age from 16 to 56.
David Melenkevitz, a spokesman for the DEA, said his agency is assisting with the investigation but would not comment further. He said Escambia County officials have also sought help from other federal agencies including the FBI and the Bureau of Alcohol, Tobacco, Firearms and Explosives.
Nine of the couple's 13 adopted children were home during the break-in. Three saw the intruders but were not hurt. The couple also had four children from previous marriages.