Needing to get into a laptop that says Please unlock disk sda3_crypt without losing any information that might be on here. The person this laptop belonged to is no longer with us, and really need to see what is on here.
Without the password of the user in question used for encryption, there is no real way to decrypt the device and access the information. This is the point of Full Disk Encryption (FDE) - without the password needed to decrypt, there's no way to decrypt the content, so if you don't have the password you're not going to be able to get past the decryption prompt.
To that end, there is also no 'backdoor access' to an encrypted drive/partition if it was not set up with a secondary password that you had at the time. As such, there is no way to 'remove' FDE or bypass it without the password.
Unless you miraculously discover the password, you're going to be having to just 'guess' passwords until one works, or 'give up' because there's no way to remove the encryption (and the data on the system is gone forever as a result).