A Danbury man has been arrested on drug related charges.  Detectives carried out search warrants yesterday, granted as part of an investigation of fentanyl sales in the City.  42-year old Luis Yupangui-Sigua was the subject of the investigation.  During a search of his apartment, Police found fentanyl, crack cocaine, Xanax, and a large sum of cash.  He was charged with possession of narcotics with intent to sell, possession of drug paraphernalia and three counts of possession of a controlled substance.  He was held on 50-thousand dollars bond.  Danbury Police say this is part of a continuing operation in partnership with the DEA to crackdown on Fentanyl sold in the City to reduce overdose deaths.