IOWA CITY, Iowa — A decade after Colorado engineer Amir Massihzadeh hit the lottery, two state agents visited him with stunning news: He was likely the only legitimate winner of a $4.8 million jackpot he'd had to split three ways.

They told the Boulder resident that the other two people who had won the 2005 drawing were linked to a conspiracy in which a lottery insider and several cohorts had rigged drawings in several states. Now Massihzadeh, 62, is suing for the rest of the winnings that he feels should have been his.

Massihzadeh filed a lawsuit Thursday against the Colorado State Lottery, arguing he should be declared the sole winner and that the $800,000 cash prize he opted to receive should have been tripled. Accounting for 12 years of interest, he is seeking about $4 million from the lottery for what he calls a breach of contract.

It's the latest headache for state lotteries caused by former Multi-State Lottery Association information security director Eddie Tipton, who admitted to manipulating the software they used so that he could predict winning numbers on certain days of the year. Tipton, his brother, and a friend were recently sentenced for conspiring to use this insider knowledge to buy winning tickets and collect prizes between 2005 and 2011. They fixed jackpots that paid $2.61 million to them and their associates in four states, and their scheme unraveled after Eddie Tipton was caught buying the winning ticket for a $14 million Iowa jackpot that was never paid.

Massihzadeh, who received $568,900 after taxes, argues that he's entitled to the other two-thirds of the prize because the other tickets were purchased through Tipton's conspiracy and should be invalid.

"Even though the Tiptons have agreed to repay the money they received from the Lottery, the Lottery has refused to honor its obligation to Mr. Massihzadeh," his lawsuit says.

Colorado lottery spokeswoman Kelly Tabor declined to comment on the lawsuit, which is the third to claim players were cheated by Tipton's scheme.

Hundreds of thousands of people who bought tickets on dates in which Tipton could predict winning numbers are pursuing a class-action lawsuit seeking refunds, arguing those drawings weren't truly random. A man who won a 2011 jackpot is also suing the Iowa Lottery, saying his prize should be larger because the $14 million jackpot should have rolled over.

Tipton, who is serving a 25-year prison term, built computers used by Colorado and other states to generate random numbers for drawings. Starting in 2005, he secretly installed code that directed them to use a predictable formula to select numbers on May 27, Nov. 23, and Dec. 29 for drawings that fell on Wednesdays and Saturdays. The Nov. 23, 2005, Colorado drawing is the first that was fixed.

Massihzadeh had played the lottery for years, often buying a few tickets. Like most, he purchased "quick pick" tickets that computers generated for him rather than selecting numbers manually. He was "shocked and thrilled" to learn that his was one of three tickets that matched all six numbers for the Colorado Lotto, the lawsuit says.

Massihzadeh had no idea that the other two winners were part of what prosecutors have called the "ultimate 21st century inside job."

Eddie Tipton had simulated the drawing and recorded likely winning combinations by hand. He gave a notebook with those numbers to his brother, Tommy, then a magistrate in Flatonia, Texas, who traveled to Colorado to play them. One was the winner. To hide his identity, Tommy Tipton recruited a friend to claim the prize.

The third ticket was redeemed by Cuestion de Suerte LLC, which has been linked to two Texas lawyers who are associates of Tommy Tipton.

The Tiptons have claimed that the lawyers stole the winning numbers from Tommy Tipton and played them without his knowledge. The lawyers haven't been charged. But the Tiptons' plea agreements state that anyone found "to have profited from the payment of lottery prizes" in Colorado may still face restitution demands.

Timeline of the biggest crime in US lottery history

The following is a compilation of Lottery Post news coverage chronicling the Hot Lotto mystery and subsequently discovered crime.

We start the timeline with a news story indicating that only 3 months remained for the $16 million Hot Lotto jackpot to be claimed.