Dutch police arrested a 19-year-old man on Saturday on suspicion of joint responsibility for a cyber attack on the website of the public prosecution office.
The so-called denial of service attack on the prosecution website on Friday came a day after Dutch police arrested a 16-year-old youth in connection with cyber attacks by WikiLeaks supporters.
The 19-year-old, arrested in Hoogezand-Sappemeer in the north of the country, is suspected of using hacking software to launch attacks that slowed the prosecutor's website down for hours and briefly made it unavailable.
The prosecutor's office also said the man was suspected of urging other people to participate in the attack. Police seized a computer in the arrest and a replica of an Italian pistol.
Cyber activists around the globe have attacked organizations seen as foes of WikiLeaks in retaliation for the ending of services to the website after it published thousands of secret U.S. diplomatic reports.
Involvement in denial of service attacks carries a maximum prison sentence of six years in the Netherlands.
The man, who operated under the Internet alias Awinee, is also suspected of involvement in an attack on the website of online payment firm Moneybookers on Friday.
(Reporting by Aaron Gray-Block; editing by Andrew Roche)