Police made its fifth arrest to a person in connection with TalkTalk hack and blackmail case. Previously, an islamist group had claimed responsibility for the attack.

According to Wired UK, after four people was arrested with hacking charges to the UK's ISP, the fifth was arrested late Tuesday on suspicion of blackmail. The first four arrests took place over a week at the end of October and beginning of November. A 15-year-old in Northern Ireland, a 16-year-old in London, a 20-year-old in Staffordshire, and a 16-year-old in Norwich was arrested. They all have been released on bail until March. 

A Russian cyber jihadi hacker group claimed to have stolen TalkTalk users' data on the attack in October. The attack was the third time this year. On February, a users data breach made its users vulnerable to fraud. One victim had been tricked out of £2,800 ($4,233) by someone claimed to work for TalkTalk and holding his personal details. In August, TalkTalk made official announcement about the attack on its mobile site that stole users personal data. The last one was in Oct. 21 which feared to affect its 4 million users.

Computer World reported, following the attack on Oct. 21, police have now arrested an 18-year-old on suspicion of blackmail. Previously, TalkTalk CEO Dido Harding said she had received a ransom demand via email. Cyber Crime Unit from London's Metropolitan Police Service and Southern Wales Regional Organised Crime Unit made the arrest in Llanelli, Wales. Curretly, the person has been released on bail. without charge while police continue the investigation.

Subsequent to the October's attack, TalkTalk reported that the personal details of 156,959 customers had been accessed, including 15,656 bank account numbers and bank routing codes and 28,000 obscured credit and debit card numbers, as quoted by Computer World. Although data breach is less than predicted, the attack itself could cost the company up to £35 million ($53 million).

Engadget also reported the aftermath of attack. UK's Culture, Media and Sport Committee has launched an inquiry into the attack, focused on TalkTalk's cyber-defense. The inquiry will also require the broadband Internet service provider to provide evidence. Culture, Media and Sport Committee a parliamentary committee consist of 11 MPs, representing multiple parties. The inquiry will also put an interest on wider telecommunication and ISP industry, and whether it can do more to protect customer data.

Attack on big telecommunication company brings very serious consequence as it will endanger millions of users. Therefore, improving cyber-defense has to be on highest priority list for telecom companies and ISPs.