Miller, managing director of Citigroup's environment and social risk management team, was discovered on Tuesday in the bathtub of his upscale Greenwich apartment with his throat slashed. The NYPD told CNBC on Wednesday that the incident was likely a homicide, since a knife was not found.
But sources told Daily News on Thursday that investigators found a knife under the body, which may indicate that Miller cut his own throat and fell on top of the knife in the bathtub.
A NYPD spokeswoman declined to confirm the discovery of a weapon with CNBC and said the medical examiner will determine the final cause of death. The medical examiner did not immediately respond to CNBC's inquiry for comment.
The banker is suspected to have committed suicide after a drug and alcohol binge, the Daily News said. Detectives told Daily News that there was evidence of drugs and alcohol use in the apartment, including what looked like crystal meth.
A surveillance video from Miller's apartment elevator showed that Miller may have been arguing with an unidentified male, Daily News reports. The man exited Miller's apartment late Sunday or early Monday, sources told Daily, and Miller told the doorman not to allow him back inside.
Records indicate that since Monday, at least two 911 calls were made by a caller from inside Miller's apartment, sources told Daily News. The caller could have been Miller, who complained in one of the calls about a person stalking him outside the apartment.
Inside the apartment, investigators did not find any signs of a struggle or break-in, Daily said.