Reference

According to various sources, Willem van Eijk, a convicted Dutch serial killer, was sentenced to 18 years imprisonment in 1974 for two murders. He was released in 1990. However, he started killing again in 2001 and was re-arrested. The duration of his sentences is not explicitly stated, but it can be inferred that he served at least 16 years (1974-1990) for his initial crimes and an additional sentence for the later murders, which is not specified.

Here are some relevant sources:

• Wikipedia: "Willem van Eijk" - "He was sentenced to 18 years imprisonment in 1974 for two murders, released in 1990."
• Murderpedia: "Willem van Eijk" - "He was sentenced to 18 years imprisonment in 1974 for two murders, released in 1990."
• Keller On The Loose: "Serial Killers: Willem van Eijk" - "Van Eijk was sentenced to eighteen years imprisonment in 1974 for two murders, released in 1990. He started killing again in 2001 and was re-arrested."

Image: Willem van Eijk

Please note that the exact duration of his sentences is not explicitly stated, and further research may be required to determine the exact length of his sentences.