Natalee Holloway's Father: Declare My Daughter DEAD

Natalee Holloway's father is looking for some closure in the case of his missing daughter -- asking an Alabama court to declare her dead once and for all ... over SIX YEARS after she disappeared.

Dave Holloway filed the petition back in June for presumption of death -- a legal declaration that a person is deceased in the absence of hard evidence ... provided the person has been missing for five or more years.

In the petition, obtained by TMZ, Dave rehashes the entire heartbreaking case -- beginning with his daughter going missing in Aruba back in 2005 during a high school graduation trip.

Despite an "exhaustive investigation," Dave claims he is no closer to finding his daughter after all this time and he's ready to call it quits -- adding, "It is my firm, however painful, belief that my daughter Natalee is deceased, and not a runaway."