Sussex Police: We are investigating two cases of arson with intent to endanger life at two houses in Vale Road, Seaford, in which lighted rags were pushed through front door letter-boxes while people were asleep inside.
Also being investigated is fire damage to vehicles parked outside both addresses and further damage to one, a Jaguar, when the marque's symbol was prised from its bonnet.
All the offences occurred overnight on Saturday and Sunday, 23 and 24 February, and detectives believe they may be linked.
One householder shouted at a boy and a girl, both aged around 16, who he saw tampering with the Jaguar on Saturday evening, and there is a strong possibility that they may have been involved.
Investigation supervisor Paul Sellings said: "It is extremely fortunate that no one was seriously injured in these two incidents. In both cases people, including children, were asleep indoors when lit rags were pushed through their letter boxes.
"The attacks were potentially fatal and we are extremely keen to identify and arrest the suspects without delay. We'd ask anyone who saw anything suspicious, who may have relevant dash-cam footage or who has any information about who may have been responsible to contact us immediately."
They can do so online or by phoning 101, quoting serial 149 of 25/02. Alternatively, they can contact Crimestoppers or call the independent charity anonymously on 0800 555 111.