Kane County prosecutors continued to assemble their timeline showing how, they say, Richard Schmelzer drove from a Dallas suburb to East Dundee in July 2014 to fatally stab his grandmother, Mildred “Dodie” Darrington, as an American Express Card investigator Wednesday detailed gas purchases made from Texas to Oklahoma to Missouri to Illinois and back on a gift card.

Schmelzer, 44, was deep in debt and cheating on his wife when he decided to kill Darrington to collect his share of her inheritance after other sources of borrowing money dried up, prosecutors argued.

According to earlier testimony, he used a fake name to buy a “go phone” shortly before Darrington’s body was found fatally stabbed in her own bed the morning of July 18, 2014, after she failed to show up for a hair appointment that morning.

Prosecutors said Schmelzer used that phone, which he thought was untraceable, to check the balance twice on an American Express Gift Card he bought in Frisco, a Dallas suburb, where he lived with his wife and four daughters.

Christine Kulagowski, a senior special agent with American Express, testified that the gift card was purchased the afternoon of July 16, 2014, at a Frisco supermarket and loaded with $250.

The next day, the card was used to buy gas in Texas around noon, then $27.97 worth of gas in Big Cabin, Oklahoma, at 5:44 p.m., Kulagowski said. At about 11 p.m., the card was used to buy $3.25 of food at a McDonald’s in Collinsville, Illinois, she said.

At 3:11 a.m. July 18, the card was used to buy $37.38 of gas at a Thornton’s off Route 31, north of I-90, in West Dundee, and again at 10:13 a.m. in Valley Park, Missouri, for $30.40 in fuel and again at 2:26 p.m. at the same location in Big Cabin as Schmelzer worked his way back to Texas, she testified.

The next two purchases were the morning of July 19 in Dallas and Addison, Texas.

Christopher Bivens, who was manager at the West Dundee Thornton’s in July 2014, testified that a gas purchase was made at 3:13 a.m. July 18, 2014, and that the last four digits on the card matched the American Express Gift Card that prosecutors argue Schmelzer bought.

According to an affidavit used to secure a search warrant, Schmelzer borrowed a car that was rented by a male friend and put 1,920 miles on it in two days. The car also was caught in a toll violation on I-355 near Bolingbrook.

Defense attorney Joshua Dieden has argued that authorities rushed to judgment against his client and that the state’s case is circumstantial, lacking direct evidence such as DNA at Darrington’s home.

The trial is expected to conclude early next week. If convicted of first-degree murder, Schmelzer faces 20 to 60 years in prison. He is being held at the Kane County jail on $5 million bail.