Summary from Goodreads:

Far out in the asteroid belt an alien spaceship of colossal dimensions is discovered. Initial investigations of its vast, gothic interior reveal a number of humanoids preserved in a state of suspended animation. At last, there is real proof that intelligent life does exist in other galaxies. But when three of the beings are brought back to Earth, disaster strikes. The humanoids are discovered to be vampires-preying on people's life-fields, sucking the body's energy with a kiss of death. Suddenly one of the vampires - a female of extraordinary beauty and sexual allure - escapes. And the desperate hunt to track it down soon develops into a psychic struggle for the survival of the human race

Also titled The Space Vampires.