It looks like senseless violence, but it really is not. Islam teaches that non-Muslims deserve to live only as long as Muslims allow them to, and they can torture or kill them at will simply because they exist. Therefore, kidnapping somebody and setting them on fire is really not a problem in Islam because non-Muslims are not human:
A Catholic woman was doused with gasoline and set on fire in the village of Kajura, Jessore district (southwest Bangladesh). The woman, named Maya Karmokar, was asleep in her bed when unknown persons entered the house and attacked her.
Her desperate cries attracted the attention of relatives, who arrived just in time to save her life. Rushed to the hospital, doctors found burns over most of the body. Now, however, she has returned home and is under the care of a local doctor, because she can not afford specialized medical treatment.
The attack took place Sunday, July 9, just 15 days after the massacre in Dhaka, where five Islamic terrorists killed 20 people. Yesterday the local police returned to the place of the attack and gathered information. The criminals are still unknown.
She remained hospitalized just for one day and had to return home because they can not afford better treatment. She says: “I have no enemies, I do not know why they want to kill me!”. (source)
This woman had no enemies, and yet the Muslims still attacked her just because she was a Christian. That is the true face of Islam- it does not matter who you are, all that matters is if you are a Muslim or not, and if you are not a Muslim then your life is only permitted to exist as long as the Muslims allow it, and they can take it with impunity when they choose to.