Several Philadelphia homicide detectives who investigated the fatal shooting of Officer Moses Walker Jr. in 2012 testified Monday that they did not recall receiving any significant information from a witness who later received $20,000 in reward money with the support of then-Detective Philip Nordo.

On the witness stand Monday at Nordo’s sexual assault and corruption trial, four of his former colleagues said they were either unaware of, or could not remember, the witness providing tips that helped lead to the apprehension of the two men later convicted of killing Walker. Instead, the detectives cited information provided by several women as key in making the arrests.

“I had never heard of [the witness],” said Det. Thomas Gaul.

“Not that I recall,” said Det. William Joyce, when asked if the man provided valuable information in the case.

Prosecutors sought to elicit that testimony because they have charged Nordo with defrauding city reward funds during his time on the force — and because they say Nordo later raped the witness who received the cash.

That man was one of three witnesses who has taken the stand during Nordo’s trial to accuse him of abuse during investigations. (The Inquirer does not name people who say they were sexually assaulted without their permission.)

Prosecutors have charged Nordo with crimes including rape, sexual assault, and official oppression.

Nordo has denied all wrongdoing.

The testimony Monday marked the beginning of the second full week of Nordo’s trial. Unlike last week, when jurors heard from the former detective’s accusers — often in long or emotional turns on the stand — everyone who testified Monday was a current or former police officer or lawyer.

Nordo’s attorneys, during cross-examination of the detectives connected to Walker’s case, sought to show that many officers were part of that investigation, and many witnesses were questioned — suggesting it would be possible for them to not know everything that led to the suspects’ arrests.

Attorney Richard J. Fuschino Jr. also pointed out that although Nordo wrote a memo supporting the witness’ bid for reward money, it was signed by several of his supervisors. Some of Nordo’s ex-colleagues, under questioning, also said Nordo was known in homicide for his skills in submitting paperwork or documents supporting reward applications.

Testimony was expected to continue Tuesday.