Slain Irishman Jason Corbett was worried about his wife's spending habits shortly before he was killed.
It is also claimed murder accused Molly Martens Corbett removed large sums of money from joint accounts after his death.
Police officers who investigated the killing in North Carolina also believe Mr Corbett intended to permanently return home to Ireland with his two children, raising the prospect of a split with his second wife.
The allegations are contained in affidavits filed by detectives in support of search warrants they secured as part of the investigation into his death on August 2 last year.
The records show how detectives mixed long-established investigative techniques with newer forms of inquiry, including tracking information stored by Google and Facebook and a number of banks, as part of the probe.
Ms Martens and her father Thomas (65) were charged with Mr Corbett's murder earlier this week.
One detective, WS Thompson, outlined how the Limerick-born pharmaceutical company worker had been planning a trip back to Ireland on August 21 "allegedly for the purpose of moving him and his minor children back to his native homeland permanently".
In preparation for that trip, Mr Corbett (39) had discussed transferring $60,000 (€55,200) from US bank accounts to his home bank in Ireland.
"Investigators also learned from members of the Corbett family that Jason Paul Corbett was possibly concerned about the spending habits of his American wife," WS Thompson's affidavit said.
It said his plans to return home and his wife's spending habits "were allegedly a source of conflict between the couple".
Attorneys handling Mr Corbett's estate also told detectives "large sums of money" were removed from joint accounts he held with Ms Martens after his death.
"Jason Corbett's alleged comfortable financial status provides additional possible motive for his untimely death," the document said.
As part of the probe, police also seized Mr Corbett's Dell Latitude computer.
Monthly bank statements dating back five years were retrieved by detectives, while a warrant was also secured for the search of a locker at a nearby golf club where Mr Corbett was a member.
Phone records for Mr Corbett, his wife and her parents, who were both in the house on the night of his death, were also seized.
The purpose of this was both to establish who had been communicating with who, but also the location of their phones at various times.
Another detective, BM Smith, revealed in an affidavit that police did not believe the account of events given by Ms Martens and her father Thomas about Mr Corbett's killing.
Detective Smith said the scene was not consistent with claims by Mr Martens that there had been an uncontrolled fight prior to the killing.
Mr Martens claimed he hit Mr Corbett with an aluminium baseball bat because he was choking his daughter and had said he would kill her.
However, the detective noted there was no sign that either Ms Martens or her father were injured.
According to detectives, Mr Martens admitted to detectives that they struck Mr Corbett in the head with a concrete paving brick and an aluminium baseball bat.
However, discrepancies have also emerged over Mr Martens' account of where he got the baseball bat. Mr Martens indicated he brought the bat to the residence as a gift to his step-grandson, Jack Corbett, but hadn't yet given it to him.
However, police suspect the bat used was one given to Jack the previous summer which was stored in a sports equipment bag in the garage.
If true, this undermines Mr Martens' story that he picked up the bat because it was close to him.
Ms Martens and her father are both facing second degree murder and voluntary manslaughter charges.
Each could receive up to 40 years in prison if convicted.
Both are set to plead not guilty and claim they acted in self defence.