Walshe appeared in Quincy District Court in Massachusetts Wednesday morning ... the day after prosecutors charged him with murder and improper handling and transport of human remains.

Prosecutors ticked off a laundry list of evidence they say proves Walshe killed his wife around New Year's Day before dismembering and disposing of her body. Among the evidence ... a bloody knife in the basement of their home.

Authorities also found a hacksaw, hatchet, rugs, and a COVID vaccine card with Ana's name on it at a nearby trash site -- in a dumpster taken from his mother's apartment complex.

And there's this ... prosecutors say Walshe searched the internet for information on how to dispose of a female body that weighs 115 pounds. And on their son's iPad, there were searches for "How long before a body starts to smell" and "How to stop a body from decomposing."

In addition to the other evidence, Walshe allegedly paid $450 in cash at a Home Depot -- where he's seen on surveillance video -- buying cleaning products, tarps and mops.

Before they married, Ana had contacted authorities, telling them Walshe threatened to kill her.

Walshe is being held without bail.