A jury at the Central Criminal Court has heard Patrick Quirke said Mary Lowry's answers to his questions about her boyfriend's disappearance were "intriguing" and "strange".
Garda witnesses were giving evidence in the trial of Patrick Quirke, of Breanshamore, Co Tipperary, who is accused of murdering Bobby Ryan, a part-time DJ known as Mr Moonlight.
Mr Quirke has pleaded not guilty to the murder of Mr Ryan at an unknown location on a date between 3 June 2011 and 30 April 2013.
Mr Ryan's body was discovered by Mr Quirke on Ms Lowry's farm at Fawnagowan, Tipperary.
Inspector David Buckley told the court that in a voluntary interview on the day Mr Ryan’s body was discovered, Mr Quirke said he had no knowledge of what happened to Mr Ryan other than what Ms Lowry had told him.
He said he found what she had to say "intriguing" as she could not be clear whether he left her yard two or ten minutes after leaving the house.
He was also curious about how she found his car so quickly at Bansha woods, when it was on a route that Mr Ryan would not usually have driven.
He told gardaí: "When I asked how she could have seen his van from the road she said she couldn't, she just drove in. I found it intriguing, she had a 'couldn't care less' attitude about it.
"She said her friend who worked in a shop had a conversation with a sales rep who passed the van that morning. I told her she should contact him and she would not contact him," he told gardaí.
"I also drew on the fact that she said she had not heard any car drive into the yard that morning, so I kept asking her on and off on different occasions and she was certain a car didn't enter the yard. I found this answer strange because on several occasions I was in the bedroom with her and the doorbell would ring and you couldn't be certain if a car had driven into the yard."
"I suppose like everyone else I had a hunch of what happened... Everyone had notions, was he attacked? Did he leave for Spain? I asked questions, I thought the answers strange. I read too much into it."
When asked by gardaí if an outsider looking on might think he had a motive to dislike or harm Mr Ryan, Mr Quirke said: "Maybe, but that's not true."
Inspector Buckley told the court he interviewed Mr Quirke after taking him from the farm to Tipperary Garda Station.
When questioned about Ms Lowry's relationship with Mr Ryan Mr Quirke said he assumed gardaí knew he had an affair with Ms Lowry but he did not disapprove of her new relationship.
He accepted Mr Ryan was possibly the reason Ms Lowry had ended their affair, but said they had not discussed it candidly.
He told gardaí he had no issue with Mr Ryan and said he never went after him or had any heated discussion.
He said he did not meet Mr Ryan on the farm on the morning he disappeared and did not know all along that his body was in the underground tank.
He also responded: "These are nice questions now lads".
Mr Quirke agreed it was probably fair to say he still had feelings for Ms Lowry.
Gardaí suggested it could not have been easy to see her with Mr Ryan and had to have bothered him.
Mr Quirke said: "No more than it was for her to see me with my wife."
Asked why he did not show gardaí the underground tank when the farm was being searched and the slurry tanks emptied after Mr Ryan's disappearance, he said "I didn't think of it. I thought it was laughable to be emptying the slurry tank."
Asked if it was because he knew the body was there, he replied "No".
He said he did not know who else knew about the tank apart from Martin Lowry, his late brother in law. The last time he was near the tank was in 2008, he said.
On the day he found the body he said he had moved back a concrete slab to draw water from the tank for use in mixing with slurry that he intended to spread on paddocks.
Firefighter Bernard O'Brien, who led the operation to retrieve the remains of Bobby Ryan from the tank, told the court no one suggested waiting for the arrival of a pathologist before the operation began.
He said he and eight colleagues attended the scene at Fawnagowan and took part in the operation to retrieve the body from the tank.
He said it was a difficult operation due to the confined space in which they had to work and the special chemical suits required.
Only four members approached the tank and others remained further away in a decontamination zone.
He said he requested that gardaí remove one of the concrete slabs to allow two members of his team to access the tank.
During cross-examination he said no one suggested waiting for a pathologist or forensic science lab personnel before removing the slab or recovering the body.
Asked if he could see that the body was naked he said he could see an outline of the ribs but could not tell if there had been clothing on the body. However he accepted that if the ribs were visible it suggested there was no clothing covering the top half at least.
Asked by prosecuting counsel David Humphries if he had in his 34 years' service come across any equipment that could have done a better job of retrieving the body, he said he had not.
Other members of the recovery team told the court they were unsure if the body had clothing on it or not but agreed they could clearly see the ribs.