Bitcoin prices have fallen to 15-month low and now at 3:40 a.m. Tuesday EST it's trading a little above $3,700. From last week itself, its gone down by 19 percent, however, this price crash has not affected the cryptocurrency thieves to steal as much as $5 million in Bulgaria.

Bulgarian authorities arrested three suspects Thursday and charged them with theft of cryptocurrencies worth about 5 million Bulgarian lev ($3 million), Bulgarian newspaper 24Chasa reported Monday. The suspects were arrested Thursday and two of the three men were detained following their arrest. The third man's bail was set at 50,000 Bulgarian lev, but it was unclear as to whether or not it had been paid.

The authorities seized computers that were used by the suspects to steal cryptocurrencies, as well as the stolen virtual currencies. The report by 24 Chasa said the thieves had very good knowledge of cryptocurrency trading and used "innovative mechanisms" and specialized software for the theft. Authorities also found flash drives, hardware portfolios, and notebooks were used to store account listings, as well as real and pseudo names of people that were stolen from. A car worth about 60,000 Bulgarian Lev belonging to the thieves was also seized.

It was not clear how the suspects obtained a huge amount of cryptocurrencies or even which cryptocurrency was stolen.

This seizure of cryptocurrency worth $3 million added to the much larger amount seized by the Bulgarian authorities in May 2017. The authorities at the time had seized 200,000 bitcoins when it was trading at $2,354, making the seizure worth over $470 million. According to the press release published May 29, 2017, by the Southeast European Law Enforcement Center, the authorities had arrested 23 suspects. 

On Nov. 14, a 21-year-old Manhattan man was arrested by the U.S. federal agents for allegedly stealing $1 million of cryptocurrency from a Silicon Valley executive by hacking into his phone. Nicholas Truglia now faces 21 felony counts after he went on a hacking spree and targeted six victims. This hack was done by using the SIM-swapping scheme.

In October, Gal Vallerius, known as “Oxymonster” on the dark web drug hub "Dream Market", was handed down a 20-year prison sentence. Vallerius, who was arrested in 2017, confessed to selling drugs in exchange for cryptocurrencies — including bitcoin and bitcoin cash — over the dark web. More than 100 bitcoin and 121 bitcoin cash were seized from him.

Thieves and fraudsters continue to be a major problem for the cryptocurrency industry. A report published in October by CipherTrace, a cybersecurity firm, found that $927 million worth of cryptocurrencies were stolen by hackers from several exchanges in the first nine months of 2018. The value of virtual currencies stolen from exchanges in 2017 was $266 million, signifying a nearly 250 percent increase in 2018.