The NYPD has yet to solve three open cases in 2015, including the murder of Gov. Cuomo's aide Carey Gabay.

The first case goes back to May 2014, when 18-year-old Tanaya Copeland was stabbed more than 30 times near Stanley Avenue and Linwood Street while she was walking to a friend's house. A knife was recovered at the scene, but police say they could not get a strong enough DNA match to pin the attack on a specific person.

The next unsolved case is related to the murder of Gabay, who was shot early Labor Day morning. Investigators say Gabay was caught in the crossfire between rival gangs before the West Indian American Day Parade. There is a $25,500 reward for information leading to a conviction.

Finally, police have not solved a double shooting from Jan. 2014 that left 23-year-old Gerard Grant dead on Avenue I and East 16th Street. Crime Stoppers is offering a $12,000 reward and the Police Foundation is offering another $10,000. 

If you have any information on these cases, you're asked to call Crime Stoppers at 1-800-577-TIPS.