BOSLAUGH, J.

The defendant appeals from a sentence to life imprisonment for murder in the perpetration of a robbery. He contends the evidence was insufficient to establish the death of Joseph Armstrong, the victim, was a result of the robbery and that errors occurred in the admission of evidence.

The record shows the defendant spent the evening of April 27, 1973, with Gary Wilson and his wife, Sandra Wilson, at several bars in Omaha, Nebraska. When they left Johnny's Lounge, Joseph Armstrong joined the group. They then proceeded in the defendant's automobile to the home of Armstrong's sister where Armstrong procured two $100 bills which she had been keeping for him. At some time there was conversation between Gary Wilson and the defendant concerning a plan to get Armstrong's $200.

The party then visited several bars in Council Bluffs, Iowa, and spent some time at Lightning's Club 500 in South Omaha. Eventually they drove to the Surfside Marina Club which is located north of Omaha and near the Missouri River. The club was closed but the parking lot was lighted.

The evidence is in conflict as to what happened at the Surfside Club but the jury could find that Gary Wilson and the defendant forced Armstrong to the ground and went through his clothing trying to find the $200. The defendant testified he searched Armstrong but could not find the money. Armstrong's keys and pocketknife were taken from him. The defendant testified Gary Wilson threatened to castrate Armstrong if he did not hand over the money. Armstrong tried to get away from the two men several times and eventually entered the river. The evidence is undisputed that when last seen Armstrong was in the river. Sandra Wilson, who had stayed in the automobile and was some distance away, heard a splash and a cry for help. She then heard the defendant ask Gary Wilson if he could swim. Armstrong was not seen again until his dead body was found floating downstream on May 8, 1973.

On the morning of April 28, 1973, Gary Wilson, Sandra Wilson, and Gary Tiemann, a brother of Sandra Wilson, returned to the Surfside Club and found the two $100 bills. They kept the money and divided it among themselves. Three or four days later the defendant gave Armstrong's knife and keys to Gary Tiemann.

An autopsy was performed on the body of Armstrong by Dr. Jerry Wilson Jones but the cause of death could not be determined from the post mortem examination. Dr. Jones testified there were no tests or findings which would establish conclusively whether a person found in the water under these circumstances had actually died from drowning. He was allowed to testify over objection that his findings were consistent with drowning.

In a prosecution for homicide, the State may show by circumstantial evidence the cause of death was a criminal act of the defendant. Cryderman v. State, 101 Neb. 85, 161 N.W. 1045; Morris v. State, 109 Neb. 412, 191 N.W. 717.

The proof as to the cause of death in this case was circumstantial. The testimony of Dr. Jones alone did not establish the cause of death. Because of the other evidence, testimony that Armstrong could have died by drowning was relevant. The fact that Armstrong when last seen alive was in the river and his body was found in the river approximately 10 days later would permit an inference that his death was caused by drowning. The expert testimony that death by drowning was consistent with the autopsy findings, and the absence of evidence of other probable causes, together with the other evidence, was sufficient to permit the jury to find that Armstrong's death was caused by drowning.

The defendant argues the robbery was not the cause of Armstrong's death because the robbery, or attempted robbery, had been concluded at the time Armstrong entered the river. Although the efforts of Gary Wilson and the defendant to rob Armstrong had not been successful, the jury was not required to find the plan to rob Armstrong had been abandoned. Armstrong made several attempts to escape before he entered or was forced into the river. In a statement to the police, the defendant had said: "* * * we was threatening that we was going to take him out and throw him into the water, you know, * * * and the next thing that I knew, we started chasing him towards the river * * *." The jury could have found the robbery was still in progress at the time Armstrong entered the river.

Sandra Wilson was called as a witness by the State. She had been charged as an accessory after the fact and was clearly a hostile witness and uncooperative. She had given a written statement to the police concerning the events on April 27 and 28, 1973, but it is apparent her testimony varied considerably from her earlier statement. On direct examination the State questioned her concerning her previous statement. Over objection, the State was allowed to inquire if, after she had viewed Armstrong's body at a funeral home, she had told Gary Wilson: "`* * * that it was the man, and that he and Charles Casper had killed that man.'" It has long been the rule that a witness may be examined concerning prior inconsistent statements to show his testimony has operated as a surprise, to test his recollection, refresh his memory, induce him to change his testimony, or show the circumstances which induced the party to call him. Welton v. State, 171 Neb. 643, 107 N.W.2d 394. See, also, State v. Fronning, 186 Neb. 463, 183 N.W.2d 920. Under the circumstances in this case the ruling on the objection was not erroneous. See Ewing v. United States, 135 F.2d 633.

The judgment of the District Court is affirmed.

AFFIRMED.