A college student who shared an al-Qaeda magazine in a family WhatsApp group has been jailed after admitting 13 terror offences.
Sudesh Amman, 18, from Harrow, told his siblings in a message "the Islamic State is here to stay".
The Old Bailey heard Amman also possessed bomb-making manuals and a document called Bloody Brazilian Knife Fightin' Techniques.
He was jailed for three years and four months by Judge Mark Lucraft QC.
The Whatsapp group - entitled La Familia - included images of Amman's younger siblings in poses reminiscent of so-called Islamic State supporters - such as one finger salutes and wielding weaponry, the court heard.
In messages with one family member, Amman suggested that as Yazidi women were slaves the Quran made it permissible to rape them.
He sent beheadings videos to his girlfriend - whom he said should kill her "kuffar" parents.
Amman told her: "If you can't make a bomb because family, friends or spies are watching or suspecting you, take a knife, molotov, sound bombs or a car at night and attack the tourists (crusaders), police and soldiers of taghut, or western embassies in every country you are in this planet."
The court heard that in messages to her, Amman said he had pledged allegiance to Islamic State and wished to carry out acid attacks.
Elsewhere, he asked if he could have a knife delivered to her address and told her he considered Islamic State to be the best thing to happen to Islam.
The court heard Amman also wrote of how he was thinking of conducting a terrorist attack at 'Queensbury' and had conducted reconnaissance.
The teenager had pleaded guilty last month to six charges of possessing documents containing terrorist information and seven of disseminating terrorist publications.