The Met Police said the three people discovered dead in west London were known to each other.
Works by Galileo, Sir Isaac Newton and Goya were among the irreplaceable volumes stolen in Feltham, west London, in 2017.
The 18-year-old will be sentenced this month after admitting throwing a six-year-old boy from the 10th floor of London’s Tate Modern art gallery.
An 18-year-old man was stabbed to death in West London on Thursday.
Police have arrested one man, but are still searching for two others believed to be involved.
Osvaldo Carvalho, 22, died after being attacked on Tuesday.
The victim, believed to be aged in his early 20s, died at the scene.
Fire, police, ambulance, and coastguard services were all in attendance.
A murder investigation has been launched and police are working to track down those involved.
Labour party members in West London hoping to show their support for Jeremy Corbyn in the leadership contest have been prevented