Testimony continues Wednesday in the Inland Marina arson trial.
Brenda Harris and Bill Marver are accused of setting a boat on fire in order to collect insurance money.
The prosecution believes Brenda Harris used a kerosene heater to start the fire.
The defense maintains it was accidental.
In testimony Tuesday, Evansville Fire Investigator Tim Strange showed the jury a picture of the heater the state believes Harris used to start the fire.
Strange was forced to concede the evidence was not clear when it comes to whether or not the heater was working properly before the fire.