New evidence emerged Wednesday evening in the search for UnitedHealth Group CEO Brian Thompson’s assassin, including a cellphone, a water bottle and even apparent messages on bullet casings left at the crime scene.

Around 6:40 a.m. Wednesday, Thompson, 50, was shot dead by a masked assassin outside the Hilton Hotel in midtown Manhattan, where he was scheduled to attend an investor meeting. According to police, the motive is still unknown, but new clues give investigators hope that they are getting closer to identifying the mysterious killer.

ABC News reported Wednesday evening, citing law enforcement sources, that the words “deny,” “defend” and “depose” were written on the casings found at the scene. Police sources also confirmed the written message to the New York Post, Three live 9-millimeter cartridges were also recovered from the scene and three additional cartridge cases were fired. According to the report, several pieces of evidence had individual words written on them.

CCTV footage from around the crime scene shows the killer, who police said was wearing a tan or cream jacket, a black face mask, black and white sneakers and a gray backpack, shooting Thompson multiple times before running into a nearby building fled alley and escaped on an electric bike.

NYPD Chief of Detectives Joseph Kenny also told ABC News that a phone was found in the alley where the suspect fled.

A water bottle was also found that investigators believe may have been purchased at a nearby Starbucks that the shooter had visited before the shooting, investigators told CNN.

Additionally, a candy wrapper was recovered from the same location as the water bottle, with all three items believed to be linked to the shooter – although further testing is underway to confirm this.

Police told CNN they believe the shooter could have dropped some of the items as he fled.

As the police investigation continues, DNA or fingerprints from each of these three potential clues will prove crucial in identifying the assassin, who so far remains a mystery to investigators.

Sources told CNN that police found a video this morning on Manhattan’s Upper West Side that appeared to show the suspect carrying an electric bicycle battery.

Citing law enforcement officials briefed on the investigation, the media added that it is believed the suspect may have taken the subway from the Upper West Side to Midtown Manhattan. Investigators are reportedly trying to determine whether the attacker had positioned an electric bicycle in the area, which he likely used to escape after the shooting.

Although it was initially believed that the suspect fled on a Citi Bike, law enforcement officials reportedly told CNN and NBC that the e-bike used by the suspect was not a Citi Bike. Citi bikes are equipped with a GPS system that investigators originally hoped could help them catch the killer.

When asked by the Daily Beast about Citi Bike, a spokesperson for the NYPD’s deputy commissioner of public information referred to a press conference earlier Wednesday in which the NYPD stated that the suspect fled on foot before getting into an “electric “E-Bike” got on the “Citi Bike” and rode “north on the Avenue of Americas towards Central Park”.

The NYPD’s Deputy Commissioner of Public Information also confirmed to the Daily Beast that the investigation is still active and ongoing.